I agree you don't "need" to break the rules to play high level D&D.
Really, the FIRST thing that simply needs to be done is to let go all your ideas, feelings, thoughts, restrictions, limitations, and all other self imposed things. Embrace and accept that anything is possible....yes, even that.
And for most things needed for high level play, you can fully "follow the rules" just fine. You can add a Flaming Sword of Fire that does unique fire based effects that are NOT listed anywhere in the rules. This does not "break the rules" in anyway. It simply adds an item to the game.
Homebrew, by itself, does not "break the rules". The idea that "only the hollowed game designers" can make anything is a silly and very wrong idea.