Mauxir - Lotus

If you don't have Mauxir - Lotus yet but want to try her out, she is available as a Trial Operative in Story Chapter SP8 "Reflection of Valor" (Main Story // Journey // Allies Revisited)

Lotus creates a bunch of Auxiliary units who deal damage for her, with Lotus mostly just shooting her drones to restore their HP and recharge her ult - If played properly Lotus deals literally no damage by herself, and is entirely dependent on her summoned units for damage.

Her summoned units being immobile means you need to re-summon them for each new group of enemies, which can be very annoying for casual content.
She can summon them very quickly though, so she's actually not that bad when compared to many other 5* operatives, as she can start dealing damage somewhat quickly.
She can sometimes just summon them and move on to the next group immediately, letting her summons deal with the enemies, allowing her to clear groups very quickly.
Her summoned units being kill-able means that she can perform very poorly against enemies who can kill her summoned units.
Although if an enemy can't kill them then they can potentially tank for Lotus whilst Lotus herself kites, giving Lotus essentially perfect survivability.
Lotus can also summon her Nodes in one area, and then move to another area to cover one area with her summons whilst Lotus herself does something else, such as use a turret.
This can give Lotus unique capabilities in some content, as she is generally the only character who can deal strong damage remotely, and whilst interacting with other things.
For some specific content Lotus is thus the best operative in the game by-default, as her remote-damage capability is something no other operative has.

The Basics

Role: Main DPS - Summoner
Deals Frost Damage
Weapon Type: Sniper Rifle
Her Drones deal damage for her.
Lotus ideally doesn't deal damage.
(but purely ballistic if she does)
Mobility is Average

How to use Mauxir - Lotus

If Lotus doesn't have 3 Nodes active:
Tap Lotus' Standard Skill to create 1 Node.
These Nodes will automatically create Drones.
Both Nodes and Drones are immobile, and attack automatically.
Every 10s, hold her Standard Skill to grapple to and enhance a Node
(The petals on the Nodes icon shows its remaining duration)
(Only one Node can be enhanced like this at a time.)
Otherwise, shoot your Nodes with Lotus' sniper rifle.
(This also heals them, so shoot the one with the lowest HP)

Notes:

Lotus shooting her Nodes will spawn a drone via her Neuronics, thus reducing the cooldown of her ult via her Auctus Drive A2 effect.
Lotus' ult buffs her Nodes/Drones damage by an extreme amount, and Lotus' gun deals basically no damage, so it's better for Lotus to use her gun to shoot her own Nodes to recharge her ult than shoot the enemy.
Again - Do not shoot the enemy. Shoot your own Nodes.
Nodes have a blue PBAoE around them. Stay outside of that area.
Lotus' grapple [Step.2 in the above] doesn't work if you're too close.

How to build Mauxir - Lotus

Weapon: Enlightener
Weapon Parts: Max ATK
Logistics Squad: Totem
+10.0% ATK
+106 Alignment Index
+10.6% Auxiliary Units Strength
Best supports:
Vidya - Celestial Swan (or Acacia - Kaguya if not)

Tess - Phantasia (only with her Arcane logistics)
Note:
1. Tess' support skill is useless for Lotus
2. Tess is only useful because of her ult w/ Arcane
3. When supporting Lotus, Tess' 4* weapon (Confetti Chroma) outperforms her 5* (Valiant Heart)

Your summoned Nodes have an icon to show both where they are and whether they are buffed or not.

In Co-Op, your own Nodes will always have the icon.
Nodes belonging to your allies will never have the icon.

Specifics:

Standard Skill

Tap Lotus' Standard Skill to deploy a "Mindflower Node", which is an auxiliary unit that attacks the nearest enemy every 2s, dealing Frost damage to it and up to 2 other enemies.
Lotua can have a max of 3 Nodes at a time.
Creating a new Node when at the Node cap will create a new Node whilst destroying the oldest Node.

Each Node has a 50% chance to deploy 1 "Lotus Drone" each time it attacks. Each Node can have a max of 5 Drones, or 10 Drones with the skills first Neuronic buff.
Nodes deals Frost damage to the nearest enemy every 3s.

Both Nodes and Drones deal Skill damage.

Lotus has unique HUD/UI icons to show where her Nodes are.

The Nodes have unlimited duration, but can take damage and be destroyed.
Each Drone lasts 20s, and are untargetable and cannot be damaged/destroyed, but if a Node is destroyed then all of its associated Drones are destroyed with it.

Nodes and Drones aren't destroyed when Mauxir leaves the field, but they become dormant and stop attacking.
Nodes can still be damaged and destroyed in this dormant state.

If Mauxir shoots at or through a node then it is healed for 15% of its Max HP.
With its second Neuronic buff, shooting a node to heal it will deploy 1 Lotus Drone.
This Drone deployment will proc Lotus' A2 bonus, reducing the cd of her ult by 1s.

Note that both Nodes and Drones are completely immobile.
Further note that Nodes will block your movement.
If you accidentally block your path, you will have to resummon your Nodes, as, again; when at the Node cap, summoning a new Node will destroy the oldest Node.
Also: Yes, you can use this in multiplayer to block the path of your allies.
Since the Nodes last forever, there's nothing your allies can do about this.

When Mauxir has a Node active, you can hold her Standard Skill to grapple Mauxir towards it, which also enhances the Node and all of its Drones for 10s.
Enhanced Nodes and Drones deal double damage.
Only the most recently pulled node can be enhanced - if you enhance a new Node, the old Node loses its enhancement.

Mauxir can only grapple to and enhance a Node if she is outside the Nodes blue PBAoE area.

This skill has a 0.5s cooldown and an S-Energy cost of 5, meaning you can create the max of 3 Nodes extremely quickly, and Lotus should never have any S-Energy issues.

Support Skill

Mauxir deploys 10 "Clusterbud Drones" in front of her (15 drones with its first Neuronic), which deal Frost damage to the nearest enemy every 3s.
Each drone lasts 20s.
Since this skill has a 20s duration, you can get essentially 100% uptime on it by just spamming it off-cooldown.

Since this skill has a 20s cooldown and uses 20 S-Energy, Mauxir recovers as much S-Energy as she uses, so she doesn't run into any S-Energy issues.

Each of the 15 drones deals damage every 3s, and fire a total of 6 times over their duration.
Since each drone deals 40% of Mauxir's ATK, this means that over their full 20s duration they deal a a total 3,600% damage combined.

This is extremely high for the support skill of a main-dps operative, and it makes Mauxir an ok support operative, although you're generally still better off using another support to buff your main dps, rather than using Lotus to deal damage herself.
If you're a new player though and don't have many strong dps operatives, then Lotus can be a great support simply because she herself deals good damage as a support, instead of simply buffing the mediocre dps of your main dps operative like most other supports.

Ultimate Skill

Mauxir performs a "Dance of Life" which enhances her Nodes and Drones.

After the Dance ends (which takes around 4 seconds), her Nodes/Drones are enhanced with both the double damage from her usual enhancement, in addition to a 100% Attack Speed Boost until the dance ends - which takes 10s.
The cooldown for her ult starts after this 10s Damage and Attack Speed buff ends.

Mauxir is immobile while she dances, but with her Neuronics she takes less damage and receives CC-resistance to help prevent her from being interrupted.
Since Lotus doesn't need to actually be near her Nodes to enhance them, you can just have Lotus go find a nice box to go hide in whilst her Drones tank for her, so whilst her ult does make her immobile, her ult really doesn't affect her survivability that much.

This has a U-Energy cost of 0, so Mauxir can always use it, even immediately as a battle starts (not that you'd want to, as you're better off using it after some Drones have spawned so that they can make use of the buffs).
This skill has a 50s cooldown, and it goes on cooldown only after it has ended, so it's something you can't use often.
Her Auctus Drive A2 buff can help with this, but even with max investment you'll be able to use her ult every 20s or so.
Theoretically, Lotus can reduce the 50s cooldown down to just 18s if all her shots proc her A2 and deploy a Node.
Lotus' 5* weapon can cause Drones to deploy additional Drones with a 30% chance when dealing damage, which can proc her A2 even more for even more ult cooldown.
Combined these can proc her A2 even more, potentially resulting in her ult having a cooldown of around 15s.
A 4s dance, followed by a 10s buff, followed by a 20s cooldown gives it an uptime of 10s out of every 34s, or around 30% uptime.
Given that it doubles her Node/Drone damage, and then doubles their attack speed to double it again, it's a 4x damage bonus.
A 4x damage bonus with a 30% uptime means Lotus' ult will on-average very roughly result in +90% damage as a result of her ult.
If every shot proc's her A2, then her ult is on-average very roughly doubling her total dps.
This ignores her logistics squad, which buffs her ult even more.
Even factoring in it's long cooldown, Lotus' ult is extremely strong.
Lotus' ult can increase her average dps by a factor of 2-2.5x, provided you continuously shoot your Nodes to recharge her ult.

In my experience, around 22s is a good average for Lotus' ult cooldown, and on-average using her ult that often will very roughly double Lotus' dps.

Weapon

Enlightener
Lotus' signature 5*, and her best weapon.
More Auxiliary Unit DMG, and helps deploy more Lotus Drones.
Targets taking 0.5/0.7% more Frost DMG per deployed Lotus Drone is a max of 15/21% more Frost DMG Taken, which is very strong.
Note that this gives Alignment Index instead of the more common %ATK Boost that weapons normally have, giving up to +549 Alignment Index at max.

As usual for signature 5* weapons, the "enemies take more DMG" part of her 5* is its strongest aspect, but Enlightener increasing Aux Unit Strength as well is also very strong, as that's not something found on other sniper rifles, making Enlightener even better in comparison to other snipers.

Like all Auctus Drive operatives, Lotus has no signature 4* weapon.
As such, if you don't have her signature 5* weapon, then you'll want to give Lotus the highest-levelled Semi-Auto sniper you have lying around - since most of Mauxir's damage comes from her Nodes/Drones which are Aux Units, none of the weapon effects from other weapons make much of a difference to her damage, so again - just use whatever you have lying around.
Make sure it's Semi-Auto though - Mauxir's ability to shoot her own drones to heal them mean Lotus can potentially benefit from a higher fire rate beyond just having more damage, and a lower-levelled Semi-Auto Sniper can out-dps a higher-levelled Bolt-Action sniper if Mauxir can keep her Nodes alive longer with the Semi-Auto.

For weapon parts Lotus wants maximum ATK.

Logistics

Squad

Use Totem squad - it was designed specifically for her and is her best choice.
Totem squad gives Lotus +40% Auxiliary Units DMG, which is a very nice buff, and an extra +45% during her ult's Dance, which is also really nice.

If you don't have Totem squad, use

Twilight squad - Lotus' Aux units will constantly proc the effect for a permanent -16% Frost damage resistance.
Usha squad for the extra Aux Unit buffs - just make sure Mauxir keeps shooting enemies - at least one shot every 3s.
Having to continuously shoot enemies means you can't shoot your Nodes, which is not ideal.

Lotus can't make use of Twilight's 2/3 bonus, but can make use of Usha's, so Usha does work out well.

Stats

For Stats, Lotus wants:
Basic: +10.0% ATK
+106 Alignment Index
Special: +10.6% Auxiliary Units Strength

Her Nodes and Drones inherit her ATK, so Lotus wants maximum ATK.
Aux Unit Strength buffs the damage of her Nodes/Drones.

Alignment Index gives Mauxir more Auxiliary Unit Strength.
A max-roll of +106 Alignment Index gives +8.48% Auxiliary Unit Strength.

Mauxir's Support Skill has a 20s duration and a 20s cooldown, so she doesn't need S-Energy Regen or Skill Haste
Her Standard Skill has a 0.5s cooldown, so she doesn't need Skill Haste for that either, and since Mauxir should ideally only need to summon 3 Nodes per fight, S-Energy Regen isn't useful either.
Her ult has a U-Energy cost of 0, so U-Energy Regen isn't useful for her either.
Mauxir can't heal or create shields, so Heal Bonus and Shield Construction Efficiency are also useless for her.

Since Mauxir herself deals basically no damage, stats like Crit Rate, Crit DMG Amplifier are basically worthless for her.

Whilst +8.5% Frost Damage as her special stat might seem useful, this will only affect Lotus herself, and not her summons, which is where the vast majority of her damage is.
Ideally Lotus shoots her drones to recharge her ult, meaning she ideally doesn't deal damage herself, and thus Frost Damage is literally useless.
The actual damage your weapon deals doesn't affect your Parts Break damage, so giving Lotus extra Frost Damage doesn't boost her Parts Break ability.
In practice though even if you never try to shoot enemies you'll eventually do some damage with Lotus (enemies walk into your line of fine, you miss, you want to kill a trash mob in a place your Nodes can't hit but don't want to resummon them, you want to damage a mob other than the ones your summons are targeting, etc...) so Frost Damage is a cope stat, albeit an extremely weak one.

Auctus Drive

With A1, whenever Lotus creates a Node, it automatically creates a Drone.
In an ideal fight, this doesn't affect her sustained dps by much, as your Nodes won't die, so this will only proc once per Node per fight.
If her Nodes are being destroyed a lot, then you should probably use another operative, but if you did use Lotus then A1 would be a good dps increase in that case.
Overall, A1 is not a massive dps increase, and should ideally be a tiny dps increase.
A2 reduces the cooldown of her ult by 1s for each Lotus Drone deployed.
This can result in a lot of cooldown reduction, and A2 improves the uptime of her ult dramatically.
A2 is a extremely massive damage buff for Lotus, and having A2 will fundamentally change how you should play Lotus
A3 gives a +20% Final DMG buff to all Nodes and their Drones whilst they are enhanced.
Combined with the uptime buff for her ult from A2, A3 is actually a good damage buff on-average.
With A4, when Mauxir is doing her ult Dance, all Nodes recover 10% of their Max HP every second.
This is a nice survivability buff, but obviously doesn't increase their dps unless it actually prevents them from dying.

As an Auctus Drive operative, you'll either have all of her Auctus Drives, or none of them.

Good Supports for Mauxir - Lotus

Critical Note: All of Mauxir's damage comes from her summoned Aux Units.

This section is much longer than usual, because Aux Units are weird, and thus many supports need an explanation as to how/why they work [or don't] with Lotus.
Also: Contains Maths

Essentially all of Lotus' damage comes from her summoned Nodes and Drones, which are Aux Units.
If played ideally and optimally, literally all of Lotus' damage comes from her summons.
As such, a lot of the common supports are mostly useless for Lotus, as their buffs don't affect Aux Units.

Lotus wants buffs to her ATK, AoE/PBAoE buffs to ATK that can affect her summons, debuffs to the enemies DEF and resistance, and nothing else.

Note that Lotus has a low ATK stat - her base ATK is quite low, her 5* weapon doesn't give her any ATK, and her logistics 2/3 and 3/3 bonuses don't give her any ATK.
Most dps operatives end up with 5-6k ATK when fully maxed. Lotus has around 3.2k when maxed.
Her low ATK stat means that flat ATK buffs are much more powerful for Lotus than they are for other dps operatives.
Similarly though, Lotus not having many %ATK buffs means her ATK stat is less saturated with buffs than other operatives, meaning that %ATK is also very good for her.
...Lotus just really wants ATK buffs, basically.

Aux Units and Double-Dipping

It is very important to note that when an Aux unit is created, it's ATK stat is inherited from the operative who created it, at the time of its creation.
If an operatives ATK stat changes after the Aux Unit is created, that will not affect the Aux Units ATK stat - the only thing that matters is the ATK stat of the summoning operative at the time the Aux Unit is created.
This means that you need to make sure all of Lotus' ATK buffs are actually applied to Lotus when she summons her Nodes.

This also means that some effects can be double-dipped, as you can use them to buff Lotus herself, who the Nodes inherit their ATK from, and the Nodes can then gain the ATK buff as well, allowing them to effectively gain the ATK buff twice.
If these are percentage buffs, they will stack multiplicatively with each other.

Since Mauxir's Nodes have no time limit and last forever, provided you can keep her Nodes alive, you only need to apply your buffs to Lotus once per fight, regardless of how long the fight lasts.

If Lotus can't double-dip with a specific buff, then that means the buffs apply to Lotus herself but not to the drones, which means that once you've created the Nodes there's no reason to ever apply the buff again.

Aux Units do not benefit from Skill Damage buffs, such as from Marian - Riptide's M2 buff or Siris - Freefin's Freetide buff.
(Although the Nodes/Drones can maintain Siris' Freetide buff, because the Nodes/Drones themselves do deal skill damage.)
Aux Units:
are not "full squad"
are not a "deployed operative"
are an "ally operative"

Best Supports

Vidya - Celestial Swan works by debuffing enemies, and she works just as well for Lotus as she does for all other operatives, and is Lotus' best support.
Acacia - Kaguya also debuffs enemies, and is a great support for Lotus if Celestial Swan isn't available.
Kaguya does buff Frost damage, but buffing Lotus' Frost damage isn't useful since Lotus never deals any Frost damage herself.
Kaguya is only there to debuff enemies Frost res.

Beyond debuffing enemies, how good a support operative is for Lotus is basically just a measure of how much of an ATK buff they can apply to Lotus, and whether it also applies to the Nodes and Drones as well, and with what uptime.

Overall, Yao - Nightglow is by-far Lotus' best support, but only when double-dipping her ult.
Other than Yao's double-ult, Celestial Swan is Lotus' best support, but Celestial Swan only barely outperforms Tess - Phantasia.

For now, as a percentage of Lotus' base damage, Lotus' best supports are:
(If only one operative is listed, it means that they were tested with Lotus, without any third operative in the squad at all.)
100% Mauxir - Lotus solo I'll put this at the top to re-iterate:
These percentages are total damage relative to Lotus on her own with no supports, not the extra damage the supports give.
When on her own, Lotus deals her normal damage of 100%.
1,954 / 1,844% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Yao - Nightglow (also double-dipping) + Lotus' ult (inc the RoF buff)
1,648 / 1,612% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Vidya - Celestial Swan during Lotus' ult (inc the RoF buff)
977/ 922% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Yao - Nightglow (also double-dipping) during Lotus' ult (ignoring the RoF buff)
824 / 806% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Vidya - Celestial Swan during Lotus' ult (ignoring the RoF buff)
313 / 308% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Yao - Nightglow (also double-dipping)
247 / 243% Tess - Phantasia [Confetti Chroma / Valiant Heart] (double-dipping) + Vidya - Celestial Swan
213% Yao - Nightglow when double-dipping her ult
196% Vidya - Celestial Swan (This is Vidya solo - in-practice how much Vidya adds depends who she is paired with and how much Frost Res the boss has)
177 / 168% Tess - Phantasia [Confetti Chroma / Valiant Heart]
148% Yao - Nightglow when only making use of a single copy of her ult.
148% Eatchel - The Cub with the max ATK buff from Blitzing Fangs. With her 5* Eatchel's ATK buff scales linearly from 100% to that over 20s.
136% Siris - Freefin
126% Vidya - Agave You could Agave her a bit better by using Prismatic Igniter instead of Agave's Signature weapons. She'll still be at the bottom though.
Numbers will vary slightly, as the way that Lotus' 5* gives a stacking debuff causes the numbers to continuously vary a bit over time.

Remember that whilst Nightglow has good numbers, the above are only during her ult, which she can't sustain all the time, and which has low average uptime.

Testing was done with Lotus with maxed Neuronics and Deiwos, maxed Auctus Drive, her 5* at T2, and Lvl.15 of her fixed-70% logistics set.
Your numbers will vary a bit depending on how good your logistcs are relative to mine and such (and which boss you test against and how much Frost Res they have), but that won't really change the order the operatives appear in.

Note that when supporting Lotus, the 4* support weapons outperform the signature weapons of all the operatives in the list above except Eatchel and Celestial Swan.
This is because these weapons actually give an ATK buff, whereas the signature weapons of support operatives usually don't give ATK.
The 4* support weapons are Prismatic Igniter, Strawberry Shortcake, Deep Sea's Call, etc.
Eatchel's best weapon is still her signature 5* (Blitzing Fangs).
The extra Support Skill uptime from Celestial Swan's signature weapons mean they are still her best weapons.

Viable Supports

Support operatives that do actually work with Lotus:
Obviously operatives that debuff the enemies DEF and/or Frost Resistance will always work with Lotus.
Beyond those:

Tess - Phantasia

Phantasia's Arcane logistics squad gives a +35% ATK buff to operatives within the Realm of Wonder created by her ult.
Lotus can double-dip on this - use Tess' ult to apply the buff to Lotus, then have Lotus create her Nodes - the Nodes will inherit Lotus' buffed ATK stat, and Tess will then buff the already-buffed Nodes.
Since Tess' bonus is a 35% increase, the Nodes will end up with (+35% * +35%) = +82.25% ATK buff, which is extremely strong.

Since Tess' ult can have an unlimited duration and can be moved to stay on top of all the Nodes/Drones, maintaining that ATK buff for the Nodes is trivial.

Note that the aptitude buff from Tess' support skill isn't useful to Lotus - she should be shooting her nodes anyway, not the enemy, so since Tess' support skill doesn't give Lotus an ATK buff, it's useless to her. As such, you don't ever need to actually use Phantasia's support skill.
If you have Tess' M2 bonus, you could use Tess' support skill and shoot the enemy every 5s to inflict the DMG taken debuff, but this is a dps loss as you'd use Lotus' ult less.

Tess is also on-element to Lotus, meaning she can be used with Celestial Swan, but since Tess doesn't actually deal damage when supporting Lotus, and Lotus herself doesn't do any damage either, Tess being on-element doesn't actually matter - Tess would work with Lotus regardless of what damage type Lotus and Tess actually dealt.

Further note that Tess' 5* weapon (Valiant Heart) doesn't actually provide Lotus with any buffs at all (as Lotus doesn't shoot anything), however her 4* weapon (Confetti Chroma) does provide a full squad ATK buff during Tess' ult, which Lotus benefits from.
As such, when supporting Lotus, Tess' best weapon is her 4* (Confetti Chroma), and her 5* (Valiant Heart) performs worse than her 4*.
In order, Tess' best weapons to support Lotus are:

[Best] Strawberry Shortcake - Provides a 13.2-22% ATK boost.
This is also based on the equipping operatives ATK (i.e. Tess), and Tess' ATK is much higher than Lotus.
Confetti Chroma - Provides a 12-20% ATK boost.
Chenxing's 5* weapon ( Trial's Eve ) provides a 12-20% ATK boost for 5s after an operative on the field is healed.
Given that it's a 5* weapon, and Tess will never want to use it except when supporting Lotus when she doesn't have either of the 4*'s above, it's just not worth considering
Even beyond that, healing Lotus before she uses her Standard Skill at the very beginning of a fight can itself be tricky. Again - don't even bother with Trial's Eve.
Every other weapon, including Tess' 5* (Valiant Heart)

Yao - Nightglow

Yao provides a flat ATK buff (of up to +1,500 ATK) to all operatives within the Shimmering Stardome created by her ult.
Yao's Zephyr logistics squad also gives a +30% ATK buff during her ult as well.

You can get this buff almost immediately by just shooting with Lotus' sniper a few times, using Yao's ult, and then summoning three Nodes during Yao's Stardome.
Yao's ult might only last a few seconds, but that's all Lotus needs.
Lotus will get the ATK buff from the Stardome, which the Nodes can inherit.
The Nodes will retain their ATK stat even after Yao's ult ends, so Yao's ult having a short duration doesn't matter.
This is a very quick and very easy damage buff, and is quite strong, but the time needed to get it is not insignificant in many fights.

If you aren't using Celestial Swan, you can use Yao's ult later when you have the U-Energy to do so, in order to have Yao's Stardome apply even more ATK to the nodes, as Lotus' Nodes can double-dip on Yao's buffs.
Nightglow conflicts with Celestial Swan, so you don't want to use her ult again later if using Celestial Swan, so Yao isn't an ideal support for Lotus if also using Vidya.
If using Phantasia alongside Nightglow, you can/should spam Nightglow's ult.

Even if using Nightglow alongside Celestial Swan such that you don't want to use Yao's ult again later, the damage buff Yao can provide to Lotus is still very strong.

Yao is a very good support for Lotus, but the low uptime on Yao's ult, as well as the shooting needed to get it up at the beginning of the fight does hamper Lotus' damage quite a lot, and over the length of an entire fight Yao doesn't average out that well as a result - far worse than Phantasia and Celestial Swan, although still competitive with the below.
The main reason to avoid Yao is that she's a much more tedious operative to play, as you do actually have to shoot the enemy to get U-Energy to use Yao's ult at all.

Similarly, Lotus doesn't generate any U-Energy herself, so you normally won't get enough to use Yao's ult at all, and actually shooting the enemy with Lotus gun is a huge dps loss, as shooting her Nodes is much better.

Overall, Yao can be very strong in prolonged fights, and if you have a second support that can actually generate som eU-Energy she can be great, but in 99% of fights Yao simply doesn't average out that well, and is a pretty poor choice.

Eatchel - The Cub

Eatchel's usual ATK buff is strong, and provides the drones with a good ATK buff.

Eatchel can also heal Lotus' Nodes, although since Lotus' optimal playstyle is to shoot her own Nodes to heal them and reduce the cooldown on her ult, which also heals them, Eatchel's healing isn't overly useful as Lotus heals her Nodes for much more than Eatchel does, but the extra healing Eatchel provides is still nice.

Whilst Eatchel can be very good for Lotus, Eatchel needs some time in order to max her ATK buff, which isn't practical for most fights.
As such, Eatchel is a fantastic support for Lotus in general content, but in boss-only fights like Neural Simulation Eatchel isn't that good of a support for Lotus.

You could just immediately use Eatchels Support Skill to instantly heal and get an ATK buff, but that will be much lower than the max that her 5* can give, and that ATK buff on its own isn't actually that strong, so this isn't something you'll want to do.

Siris - Freefin

With her M5, Freefin provides a +15% ATK buff, which is a good buff.

Freefin also provides a flat ATK buff equal to 1% of Siris' Max HP (so probably around +500-600 ATK depending on your investment) if you have at least 10 Wavehunt stacks.
Siris' Neuronic and M1 buff can give Lotus Wavehunt after using Siris' Support Skill, so getting Wavehunt isn't a problem for Lotus.
Lotus can't double-dip on this buff, but it's still a strong damage bonus.

Freefin's Libra logistics squad provide a +25% ATK buff when the deployed operative has both Freetide and Wavehunt.
Again, getting Wavehunt isn't hard to do, and it's a good buff.

Lotus' Nodes and Drones do accumulate Freetide for Siris, and as such Siris' Support Skill won't expire, which makes Siris pretty easy to use as a support.

Since Lotus can't double-dip on any of Freefin's buffs, you just use Freefin's Support Skill immediately, summon your Nodes, and that's it.

The lack of double-dipping means that Siris is not an overly strong support for Lotus when compared to the above, but she's still good.

Vidya - Agave

Agave's support skill provides a 20% ATK buff, which Agave can supplement using Prismatic Igniter to turn her into an actually quite good support for Lotus.
She's still a cope support and performs worse than all of the above, but Agave is one of the very few operatives who provides an ATK buff with no strings attached, meaning she is one of the very few operatives who can actually buff Lotus without relying on a 4* support weapon, logistics squad, or otherwise changing her default loadout in any way.
(Although if you want to use Agave as a support you should change her weapon...)

Any operative with a support weapon

The 4* support weapons (Prismatic Igniter, Strawberry Shortcake, Deep Sea's Call, etc.) all provide a 15s ATK buff to the deployed operative after their equipping operative uses their support skill.
Operatives using these weapons work well with Lotus, as their ATK buff can end up being quite large due to Lotus' inherently low base ATK stat.