When I first learned Haskell it took a very long time before I started figuring out what monads, applicatives and category theory were, and even then I only ever took a deep dive into monads specifically, basically so that I could do side effects.

For a long time in the beginning I was just learning about the basics, like list manipulation functions, and typeclasses. There was quite a journey in between beginning Haskell and even starting to look at the learning material for monads/functors etc.