I used to think Kiara. Nonwithstanding whether you like her /wish her gone or not in general, she was the prime candidate for a menhera meltdown because she combined the most points for it.
>outspoken personality, previous twitter activity shows she's the type to engage in public meltys
>got dealt a shit hand during her first months in japan, tech troubles, rat house, alone and missing friends
>lowest subbed EN, which wouldn't hurt if she didn't care, but she does because she still has residual numberfag idol trauma
>especially sensitive to affirmation, but also gathered (due to her own fault or not, you decide) a dedicated anti brigade to tear her down.
and so on.
But now, after about a year and she's still here without having blown up, I think she's "safe" (as in, a big menhera meltdown didn't become more likely over time, only less likely). The Hololive money is rolling in and affording her a comfortable lifestyle where she doesn't have to worry about the basics anymore. She's back home with friends, family and as much as they annoy me, her fucking cats probably do wonders for her mental stability. She's apparently finally starting to see docters/therapists for her health issues. Other potential pitfalls (for example, the scary imagined sjw bogeyman) have also been avoided professionally. And as much as the haters still shit up veetee, in terms of actual on-stream damage they're insignificant and easy to ignore, and she seems to have gotten better at it, or at least is just more selective in her egosearching. Also for all the trouble an outspoken personality might bring, it's probably better in the long run if she airs her minor grievances out from time to time to let off steam instead of just bottling it up because that's when the one big blowup is going to happen. So, if she hasn't melted by now, I think it's fair to say she probably got strong enough that she's not the weakest link anymore.
Now, as for what happens in the future, or who the next possible candidate is, I don't know, it's still too early with the new Gen to tell. If they can get over the initial bump of the "boyfriend drama" and show that they don't care, it'll settle itself down (just like it did with other girls before). Only if they continue to show weakness, and therefore show their haters that it works attacking them, they will fall.