[AnimalMuppet]

You're either going to ask to get taken off of management, or you're going to quit, or you're going to just try to suffer in silence until you do one of the first two.

I'd try the first one. The third one is damaging you. Yes, you've improved your ability to cope with the damage, but... my father suffered through a job he hated for seven years. I saw what it did to him, and what it did to his family. Yeah, I know, every job has parts that you don't like, but some are worse than others. If it's bad enough that you need out, you'll know. Even if you can cope... why live under that burden for the next X years?

If you go to your boss, the problem is that you were his way of escaping from his intolerable situation. He likely won't be open to you wanting out, unless you offer him an alternative. "I think Person Y could be good in this role; I can stay in it for two months to help them get up to speed."

If they don't take it, then you can look for a new job. (Don't leave the old one first if you can help it!) Tell the new people straight out - "I don't want to be a manager; I want to be a senior contributor." Some places will reject you for that reason - they think all senior people have to become managers. But some will be fine with it. It just may take a bit of looking.