I wouldn't qualify myself as a great programmer, but I never had the feeling of reaching a wall. There are just so many things to explore. I would just pick a l

I wouldn't qualify myself as a great programmer, but I never had the feeling of reaching a wall. There are just so many things to explore. I would just pick a language or area I'm not familiar with and try to work on some project. Write a (mini)C compiler in OCaml. A distributed reliable key-value value store using the Raft protocol in Go. Work on some toy OS in C. A Gameboy emulator in Rust. A doom-like game in C++. Do 500 leetcode problems. It's endless! I personally like to pick up some programming projects from MIT or similar institutions. Considering you're self taught, you may benefit from more academic material. Just pick something that corresponds to your level.