As has been pointed out by philosophers for a long time, there is no inherent meaning, beside what you yourself create. For some people, children. For others, art of some sort, or building a business that creates value. For some, pure hedonism, or building relationships and helping the people around them.
I'm way older than 50, and don't miss having kids at all.
My impression is that voluntarily child-free people have a very low regret rate, but there are dozens of conflicting studies on this. Interested if you have anything concrete to link to.