I’ll try. I’m self taught and spent years learning enough to convince an employer to pay me more than an entry level wage because I was career changing in midlife with a family to support and couldn’t afford to take a pay reduction to switch industries. Anyhow, I have for years spent 10s of hours a week studying to level up and still do. But my studying is and always has been entirely aimed and increasing my earnings.

So before I got that first job, I focused on learning general things to raise my ceiling, so I studied text books. OS, DS and Algos, Calculus, DB Implementation, and others.

Now that I have my job, I’ve focused on the areas that i am tasked with in my day job, like DB deep diving and Statistics and Linear Algebra.

I always felt that any side project I would focus on would impose too high an opportunity cost because I fealt I was learning better things.

I am still growing and will continue to grow as long as I’m in this field but my github has nothing noteworthy to show off.

That said, I believe your point is correct in the abstract, namely, that Devs who spend time outside of the office to level up will be better than those that don’t All Other Things Being The Same, I’m just saying that side coding projects isn’t the only instantiation of that activity