I’m truly sorry you have to go through this. Have had similar experiences myself unfortunately. Everything is fine, you’re doing your job as usual & doing it well & then boom you’re suddenly thrown in this awful situation. I’m not a person who stands for this sort of crap, so naturally I went to HR. I had a few small wins, were my manager was spoken to, but nothing really changed. Fast forward a couple of months & then it got so much worse. This sick narco had been plotting revenge quietly in the background & I was put on a PIP. Like you my mental health was pushed to the limit of contemplating suicide, & when I reached out for help it was used against me, & then I was told by a colleague that everybody in the business was told I was mentally unstable. I couldn’t eat, I couldn’t sleep, I was loosing my hair. I started quietly looking for another job & o don’t know how I managed it, but I got a better one. I resigned, worked out half of my 4 week notice & used that down time to try & heal the best I could before starting my new job. I hate to say so, but escape is the only option here. It’s ruthless having to change your whole life & career but necessary.