I'm not the archetype you were asking for, but I am later-ish in my career (40 years old). I co-created a startup not all that long ago (little over a year). I don't regret creating a startup, but it is very very hard at times in ways I did not anticipate. So, there are times when I'm very envious of my former self. Where I got to deal with the perils of regular employment rather than the perils of being an employer. Thoughts like, "Ah, I remember the good old days when this kind of thing was somebody else's problem to deal with. Those were good times. Good times. Welp... (rolls up sleeves to try to figure out the least bad decision from a mountain of uncertainty)"

That's despite having previously operated a moderately successful small business and also helping lots of other companies take on difficult technical challenges and get their products to market. So, there are a lot of things that I had my eyes wide open to that sometimes less experienced founders I know end up a bit blindsided by.

I can't speak for anyone else, but I can say for myself that if my motivation for undertaking this were rooted primarily in the possibility of regretting not having done it, said FOMO would probably not provide the sustaining fortitude necessary to keep pushing and pushing and pushing through the numerous challenges in fundraising, development, go-to-market execution, etc. etc.

So, my only real bit of commentary would be to do a startup because you're dead certain that's the thing you want/need/should do to achieve some goal about something you want to change about the world, the marketplace, and/or the state of technology, etc. I'd not suggest doing it on the fear of regret of not doing it. If that makes any sense? That said, if you have a goal or ambition like that, then I'm always supportive of folks who want to go out there and grab ahold of entrepreneurship and ride it either into the dirt or into the sunset.