Coupled with the fact that, as you yourself pointed out, there is a literal endless amount of work to do, forever. This is also due to the nature of the company being so big.
All companies always has work to do, and no one is ever «done», but in a giga-enterprise all meaningful deadlines and deliveries sort of tangentially rounds down to zero in terms of impact.
I almost burned out from this myself working in Microsoft. I was succeeding in my work by most metrics, but I am motivated more by my work being MEANINGFUL and having impact more than anything. That is almost impossible to achieve in any large enough company.
Jumped off to be a startup CTO and life started smiling again instantly.
Take time away from work, but not too much time. Comments such as «it takes years» can be true if you have ground yourself down to a nub, but trying (and being ok with failing) to do some work that lets you feel like you mean something and contribute back to society is an understated and important part of the healing process.
Good luck!