People remember your kindness. That’s it.
I’ve had several senior neighbours who passed away, after decades of living alone. We’ve always helped each other in one way or another and when they passed, in all cases I thought back about the last time we talked. In all cases the conversations remembered involved kindness. Either from then to us or from us to them and them being grateful. It’s what remains.
Giving kindness is most satisfying. It makes the receiver happy, but it makes you happy as well in a wat that kind of lasts. It’s an interaction that compounds on both sides. I think that’s why church groups, and mentorships, ans teaching, and advisory roles are satisfying. Teaching, giving, coaching all make life far more vibrant emotionally, and far less lonely.
Giving grows the pie, while zero sum games see it as affixed. Trying to compete in the latter will make you lonely. Trying to grow the pie in any kind of local community might make you see things differently.