Jfc, imagine bringing a life in to this world for the sole purpose of them being a vehicle for your ambition

Its more that humanity is a long line of tragedy and triumph echoing through eternity, and being able to extend your accumulated wisdom to the next link in the chain is both exciting and challenging in a way nothing else in life really is.

when your kids don’t want to any contact with you anymore

That's a weird thing to say, because I've found my parents and in-laws and siblings/cousins to be absolutely invaluable. I think the modern western lifestyle may have seriously fucked this generation. And if you've become alienated from your parents AND your kids, that's definitely a shit existence.

But I would present an alternative. Don't. Stay in contact with the people you love, whether that's blood relatives or found family. Be nice to people and try to make the time together pleasantly memorable.

Then maybe your kids will want to share that experience with their kids, and you get to add another link in the chain of existence.