I recently told two people the following words of wisdom, in different contexts:

You'll do what you'll do. You can always do 2x more but you won't; you'll only do what you'll do. If you do more then that is what you'll do. You've done all that you would do. If you imagine every other way it could have gone, you're seeing another universe; you won't have what that person has. Appreciate what you have, and focus on your strengths.

It's a wisdom I taught myself to avoid burnout. It usually works.