No, you'd need to account for several things (curing someone of malaria has compounding returns, high-impact opportunities may dry up, etc).

There's substantial discussion:

https://forum.effectivealtruism.org/posts/7uJcBNZhinomKtH9p/...

I do agree that utilitarianism provides too much room for mental gymnastics which bad actors can use to feign benevolence.

This is the smartest thing for the 99% though. While we're alive, we need the money now. Donate your estate once you're dead.

It has a side benefit of discouraging accelerated inheritance schemes.

What if you have children? You could say they "need the money now" more than you do, and never donate. You could even write a recursive will that defines N=5, and requires your daughter or son, as a condition of inheriting the money, (a) never donate it during their lifetime and (b) write their own will with the exact same text with the only change being N = N-1 (c) donation is only allowed if you are N=0, and only under agreeing to fulfill (a), (b), and (c), do you even get to have the money.