I think the only creativity killer is not using ur emotions and ur inner ear. Someone with creative passion will compose with or without theory. Either way, that music will have emotional substance.
But creativity that comes from the brain only, using theory alone, is kind of like A.I. It'll prob leave u feeling pretty empty.
To make music worth hearing, one needs to follow the muse even more than they follow theoretical maps.
Note: I think technology is a much bigger killer of creativity than theory. Too many people seem more concerned with collecting plugins, mics, amps, rack gear, etc than growing as musicians and writers.
I also think many people are developing computer-like thinking. Where visuals and mathmatic type thinking are at the forefront and the heart & emotions seem to shrink from lack of use. (It's the geek disease! 😄)
I think we'd all be better off using minimal gear and working harder on the music than on acquiring new toys. (It def helps prevent 'option anxiety' 😵💫)