[csomar]

I am also in my early 30s and noticed the reverse. I can now understand more complex subjects (like advanced probability or functional programming) that I had trouble conceptualizing when I was younger. I am not sure if it's the age factor or the fact that I have been exposed to other things and the bigger picture is becoming clearer.

My own advice would be to not do anything you won't be doing now. There is no "smarter" being. A fish is smarter than you in the ocean but I don't think that's the kind of smart you want. If you want to improve your "global" smartness or understanding, then try to explore other languages.

You can, for example, learn Arabic or Chinese. Learning Spanish is cool but if you only speak English you have been already exposed to a latin language. You can, for another example, learn Rust if you have been programming with Python/TypeScript. If you have been focused on programming for your entire career, another useful thing you can learn is psychology.

Notice all my advice converge to the same idea: learn a new way to communicate.