QALYs are generally how this done, and don't need to be limited to medicine: https://www.sciencedirect.com/topics/medicine-and-dentistry/...
They won't help you with non-existence though.
Yeah, the calculus needs to be more complex:
* not clear 2 * 50% QALY == 1 * 100% QALY
* maybe factor in "non-existence" with expected life expectancy?
* need negative QALY to factor in pain, dissatisfaction
It's just the calculus suffers from the same existential problem as abortion morality - how do you weight a lived life vs non-existence?