If you are a believer in a religion with an afterlife, as others have said, you are doing something about it.
If you’re an atheist? You accept it the same way you accept other unpleasant facts about life. Grudgingly and gradually.
When I was in my late 20s, I resented the fact that one day I would be dust. I hoped that non omnis morior. I wanted my linguistics papers laminated and buried in Svalbard.
I actually said that last bit out loud to people.
I accepted, gradually, that one day all that I was and loved and believed in and am part of would be dust. I accepted even that, if we’re not careful as a species, that might be a hell of lot sooner than the heat death of the universe. Maybe even within the century.
You may call it giving up. I prefer to think of it as growing up.
When I was in my early twenties btw, even before I was writing those papers I wanted laminated, I’d hang around this annoying guy. (Philip Newton, he was A in that XYZ and A anecdote about polyamory I wrote once.)
When I mentioned how we’d all die one day, and doesn’t that suck, he’d smirk and say “Speak for yourself.”
God I hated that guy. Don’t be that guy, OP.
The fates have had their revenge on him, for what it’s worth. He’s a middle aged management consultant with blue hair now. Blurgh.