It sounds like you're trying too hard to reason about functions as if they were, well, objects. You don't need to wrap your mind around "functional relationship

It sounds like you're trying too hard to reason about functions as if they were, well, objects. You don't need to wrap your mind around "functional relationships" because functions don't have relationships. They just take arguments and return values (which can be other functions). Functional programming is not more complicated, if anything it's less complicated. It's just different, so it requires un-learning a lot of the things you learned about procedural and object-oriented programming. And if you have a good compiler/typechecker it will do the job with much less potential for bugs.