Ultra rare characters in platinum

I'm exactly on page with the venom. Once they fix it, I'll give her another go. But for ammo detonations my Hsol is better, because no cooldowns.

I've only taken my Kineticist into all my current Platinum playthroughs and solo testing on Platinum. Largely because I've played with her the most, and familiar with what she can and can't do well the most.

Largely, I play as an opportunist. I scan the battlefield looking for enemies that have Red Bars to them under a Shield Bar, and I gauge whether I can strip it's shields or not. If so, I pull and throw off the field for immediate removal rather than let it linger and cause problems for the group. Since at XII, the 8% and 25% from equipment isn't enough to kill a Red Bar on Platinum through biotic detonation alone. So removal also means no one has to be concered about it having 1% health and restored full shields dealing 100% full damage on everyone. Just safer that way.

At other times, I provide support to others through priming and detonating. And if the time is suitable (and there's an enemy Red Bar available), a living shield for the rest through a held enemy or pair of enemies. (Blocks most hits safely, even on Platinum)

Haven't tried with the rest yet, but I gather it's basically the same: Play to the character's strengths, and not their weakness compared to the difficulty and enemy you are playing against.