I would say that the best way to start understanding the different programming languages is not by leaning a generic course about programming languages features

I would say that the best way to start understanding the different programming languages is not by leaning a generic course about programming languages features, but to pick one read about it and try to write a short project and then switch to another different language. I would start with a low level language like C, then move to a more higher level like Java and finally end with a more "modern" language like Rust or Go.