I don't know how one overcomes burnout to be honest. I tried for another year when I got promoted, set boundaries, refused stressful work, etc. Then, I just became apathetic and cynical towards my work.
I'm now in the process of changing companies. I have no idea if that helps the burnout, but I know I can't continue in my current position, even if it actually became quite low-stakes "rest and vest" kind of a position after talking to the leadership about my struggles. The damage has been done, and I could not repair it.