What worked for me was quitting and starting working as a freelancer. I'm not sure there is a burnout scale but I'd say I was around 7/10 I felt quite miserable at work. I don't think I was fully depressed but I knew that if I didn't change anything then I'd have issues.
Before I quit I did one solid project on UpWork and had about 6 months of runway funds saved and I was very lucky that my girlfriend would support me if things went south. My plan was to quit, try to find more projects and worst case start job hunting after 6 months.
Things worked out really well, I'm approaching year 2 as a solo consultant and I'm loving my job. When I think of my burnout times I realized much later on how risky my approach was and in normal circumstances I wouldn't do it.
I would advise to only follow my approach if you have a solid plan or circumstances that make it a low risk. Remember that your well being is most important. If you can be happier in a job that pays less money then it might be worth it!
