Ask HN: What do you do when you're stuck in a job and overworked? 2 years ago
You have provided a lot of detail. Well done for getting through that mess without quitting or being fired.
Book 2 weeks off if possible.
Relax for 2 weeks.
Then do 9-5 "work to rule", grind leetcode in the evenings for 3-12mths, get a $200k+ job for a proper company.