Nita - Pulse

If you don't have Nita - Pulse yet but want to try her out, she is available as a Trial Operative in Story Mission SP5-8

Pulse provides high damage with good survivability, however she has almost no mobility which can make her vulnerable and makes her ineffective against mobile enemies.
Nita making you do a minigame for the entirety of combat means that your situational awareness can be very low when playing Nita, although Nita does have very high self-healing, which means her overall survivability can be great.. or terrible, since her ult hurts her.
All of Nita's damage scaling entirely off of her HP and not ATK means that she doesn't work with most of the common support buffs, which typically buff ATK.

Nita was freely available with her 5* weapon at T2 with a logistics squad during her initial release. Many players will thus have her mostly-maxed already.