This isn't exactly what you were talking about, but one of the best pieces of advice I've heard was this: It's never worth promoting a potentially toxic manage

This isn't exactly what you were talking about, but one of the best pieces of advice I've heard was this: It's never worth promoting a potentially toxic manager into a managerial role, even if they're great in their current role. If you do, the whole team suffers. If you don't and they leave because you didn't promote them, they weren't going to let you keep them as an IC anyway. Best case is you reform them, but do that before and not after you promote them. I've seen this pattern more than I'd like.