Letting go sounds spiritual and is usually practical. It is the evening you hand the folder of printouts across the desk and then don't read any of it again at eleven o'clock.
The vigilance feels like a contribution. Mostly it is a tax — hours spent researching a thing you cannot personally operate on, paid nightly, with no return.
Putting it down doesn't mean you stopped caring what happens. It means somebody else is holding that end for a while and you are allowed to sleep.