You don’t burn out from doing too much. You burn out from meaninglessness, disintegrated beliefs, and fundamentally going against your principles.
Nishitani calls it nihility: the void that opens when what once felt real begins to lose ground.
Csikszentmihalyi, in Flow, calls it disorder in consciousness: To function, we need order in consciousness. Burnout is what happens when that order quietly collapses.
In times of dissonance, the contents of consciousness become scattered:
Psychic entropy, a disorganization of the self that impairs its effectiveness. Prolonged experience of psychic entropy can weaken the self to the point it is no longer able to invest attention and pursue goals.
The mind does not weaken from effort, but from incongruence. When beliefs and expectations are broken.
See also Change and dissonance: A proactive mindset (Repost)