As others have said, eat well and exercise (sweat) which for me usually leads to good sleep which is also key.

Is it possible that part of your “burnout” is actually dissatisfaction with never finishing? If you expect you won’t finish then motivation to start may diminish. Pick something (one thing) and focus to finish. Learn to live with imperfection. Read about the idea of minimum viable products (MVP), and apply this concept to your projects. You will find satisfaction in finishing, and then motivation to start (and finish) the next. Yes finishing is hard, but then you will have a record of accomplishments and trust in yourself that you CAN finish. Slow down and work on one thing at a time. And finish.