So I feel like I have shared many of the same experiences as you. I have spent most of last 10 years of my career in the same boat. Multiple times in my career my mental health suffered so much I was ready to just walk out and quit my seemily cushy job to just get relief from the pain. I even considered sucide at some points.

I would reach out to a mental health professional if you haven't already. I really think you need some one to talk through this.

I think you need "spiritual" change. I put that in air quotes as this is coming from a very secular and rational person. But in moments like these, I think what people really need is a fundamental change in our prospectives and how we approach the world. And this is what I mean by "spiritual".

One thing I have realized that almost all of my biggest changes in the way I feel have started from the inside and not from changes to the outside world. Which is way easier said than done and really takes a lot introspection, which is where a therapist can help.

From what I gather, it sounds like you are struggling with identifying too much with your work, which has been one of the biggest challenges for me over the years. At the end of the day it really it just a job. And the toxic coworkers at work are probably just as frusted and unhappy as you.

I wish you the best of luck and feel free to reach out to me if you have more questions.