Hustle, ambition, animation and lifeforce is likely to result in burnout, even PTSD. It is also unsustainable in other ways. It has its place but not as universal ideal.
Burnout comes from other things added onto a situation. Believe me I’ve seen lots of severe burnout at places that are “maintenance only” no-ambition shops. Burnout is much more about disenfranchisement and a big gap between motivation and requirements. Rarely is burnout a function of raw hours worked (and when it is, it’s easy to solve).