While I don't expect non-musicologists to read it, I created a music theory that greatly increases the potential for new music even over the combinatory math you have covered. However, some of it requires the future to happen but some is possible now. Basically, it proposes a way to compose music at the audio level so the sound (timbre) of the music is part of the composition on the same or higher level than the structure of the music and they work together. Between the two, it would take many times the life of our galaxy to exhaust the possibilities. However, imagination and music business can certainly limit it for now.

My college thesis in 1983 was: Holistic Tonality: An Attempt to Expand Musical Possibilities in the Face of the Third Millennium.

https://medium.com/@peter-mcclard/holistic-tonality-fe909b9c96e1