There's no such thing as "music theory".

Music theory was originally a tool for music critics in the 19th century to talk about conservatory music of the time.

There's nothing rigorous, systematic or scientific in it; it's mostly a historical cultural artifact more than anything else.

For example, music "theory" is completely helpless when describing an EDM track or how to compose one. EDM is one of the most primitive music styles ever (barely even qualifies as music in my opinion) and yet music "theory" is worthless in this case.