Comment by jpc0

I want to reiterate the points other have brought up.

Learn more about whatever domain you are writing software for, then ask what skills you need to improve to solve a problem in that domain.

Also do not get hung up on specific languages or paradigms, the overarching patterns are universal and learning them makes things significantly easier to implement.

Finally the most generic advice, Algorithms and Data structures. When you start thinking in terms of "This is the data in memory" and "This is the algorithm manipulating the data" you will "level up" quickly. Software isn't cats and dogs and random objects. Thinking in objects can be a decent way to model systems but when you get into the details you are operating on instructions and data not on objects.