I think there's too much in Western music theory that doesn't make a lot of sense, and this bothers me, since deep down, music is just math on sound waves.

Western music notation is designed for efficient reading of western classical music. It is neither designed for easy writing, nor for easy reading of arbitrary music.

Correct usage of enharmonic equivalents is crucial for efficient sight-reading. c# e# g# I can parse, memorize, and play in an instant, c# f g# is nonsensical garbage I have to treat as three individual notes rather than a meaningful unit. If the piece is written in C# major, i.e., has 7 sharps, I don't even parse those three particular notes, I simply note I am to play the tonic and move on. Its the same pattern of dots in any key, merely translated on the y-axis.

Moving the pattern to certain positions will give not major chords but minor chords. An hey, those happen to be the correct choice while the piece stays in that key. The pattern just says "play the default chord". If I need to do something exceptional — say, if I'm in the key of C major, to play A major rather than a minor, the notation explicitly signals that something exceptional is going on, by adding a sharp.

This also explains why you'd ever find an e# minor chord: going from g# major to e# minor looks perfectly natural in western notation (because it is the relative minor, a super common concept), whereas going from g# major to f minor is nonsensical, and, written in the key of g# major (or in anything from which you would sensibly reach g# major), looks completely jarring.

Western notation happens to correctly convey absolute pitches, but those are fairly unimportant to most listeners. They have shifted over time! Significantly more important for the effects that music has is how one sound relates to the next. And that's where western notation really shines, in conveying relations between notes.

And it pays of for the trained practitioner. Whereas reading music written by composers with perfect pitch who don't care about music theory is an effing pain.

Stuff like C# being the same as Db, but contextually having to use one of these over the other, just bothers me. Why would you have to call me only Andre on Tuesdays but call me Staltz on Wednesdays? It's the same person!!

Imagine somone asks you how to get to the train station. Why would you have to give them different directions depending on where they ask you? It's the same place!! You should just give them GPS coordinates, that is so much simpler and will definitely help them.