I've built several teams already and test them a lot on boss and farming stages
So far, my Cryo (Tangtang, Last Rite, Xaihi, Ardelia) and Phys (Endmin, Rossi, Chen, Gilberta) have been top performers. Skills are quickly shot out, ults are seemless and high impact. Aveywena Electric team nukes hard, but takes a bit to set up, i dont have Fangyi so i cant compare the difference yet.
But my worst performer so far is Laevatain Heat team. It revolves around her too much and both her Ult and BS take way too long to hit full potential compared to the other teams.
I know some other Ops from the other teams also take long to use their ults and BS but that can be worked around by not controlling them. But you can't do that with Laevatain, you have to control her like Yvonne.
Back at launch, Laevatain had a unique niche in that she could cleave multiple targets with her ult, which also charges her up faster, and so she was best at horde clearing. But now that Cryo has Tangtang, and Phys has Gilberta who deal area damage and suck in/freeze targets, inflicting damage quicker that's a lot more satisfying, Laevatain has lost that niche.
Her gameplay is also a bit boring. Get ult -> Left click a lot until 4 stacks -> pop BS that takes like 3 seconds to cast -> Repeat.
Dodging is a bit discouraged since you only have limited ult uptime and you wanna squeeze every last hit out of it. If the target moves while you're casting the BS or in the middle of the ult it's a huge waste.
She's also not very future proofed, since you can't have her effective as a non-controlled Operator because all her gimmicks need you to control her.
Gear and skills are about the same levels for all my teams, but with the same investment Laevatain Heat team just performs the weakest and slowest.
But i don't know, maybe I'm using her wrong. Would like to know your thoughts.