As a father of two, I would like to add that even with kids, your 30s can be a golden-age. They were for me at least.

The stress and FOMO of my twenties was gone. A certain Danny Glover quote regularly comes to mind.

Things and thoughts in my head are for the most part sorted out and now it’s time to play.

Sure, it’s different with certain responsibilities, but in the end you are yourself either way. The main point of your post, as I understood and agree with is true with it without kids. Because, as you said, success is measured in effort, not in lines of code or numbers on your watch.

We should be competing WITH each other, not AGAINST.

Now, I’m done with my thirties and the platinum age of my forties is dawning. Can’t wait.