To myself, 4 years in, I would say: OOP is just a sliver of it and the typical ALGOL-based languages you're learning are a small piece of what programming can

To myself, 4 years in, I would say: OOP is just a sliver of it and the typical ALGOL-based languages you're learning are a small piece of what programming can be. Learn functional programming now. Learn about immutability, referential transparency, and data-oriented programming. Even if you continue down the imperative, OOP path afterward, this knowledge will change the way you approach every design. There is so much more to learn, and so much more I could reveal; you'll get there, though, and it'll mean more because you did it yourself. Keep at it.