Been there done that. For me burnout is no so much about overwork. The happiest I’ve been was when I did contracting/consulting where I’d routinely work 50-60 hours a week. It’s more about feeling “trapped” in a set of circumstances, eg a dead end job where no matter what I do forward progress is impossible, project I don’t believe in, stuff like that. The solution has always been: take 6-9 months off and go elsewhere. 25 years and several major job changes later, it works. Not everyone can take this much time off of course, but you have to change your situation at least, or this thing can easily turn just getting out bed in the morning into torture.