Physicist here, something I realized when I tried to learn music theory is that the notation is unnecessarily complex and they have a sort of mythological explanation as for why things are the way they are, for example:

- why are there 12 notes and not any other number?

- Why certain notes sound well together (as in a chord)

Here is the best motivation I've seen:

https://www.youtube.com/watch?v=nK2jYk37Rlg&t=464s

(Starts at 7:44 and ends at 14:23.)

It seems like the choice of notes is due to wanting a certain amount of (mathematical) closure with octaves and fifths while also allowing for transposition.