Not sure if someone in the comments already recommended this. But I found that simply doing less work for a period of time while I got myself back on track was

Not sure if someone in the comments already recommended this. But I found that simply doing less work for a period of time while I got myself back on track was an important aspect of curing my burnout. Not caring is actually a healthy step. Care less, do less work, and if they fire you tell them exactly what happened, and go find yourself a different job. When you get this different job, set better boundaries. Eventually you will find your output increasing. Going from burnout to no work back to full work also did nothing for me. The advice around therapy and medication for potential ADHD is important as well.