I would encourage everyone who thinks "I want to apply AI to music" to look at the existing problems that creators have, talk to them, and work to bring new products to market instead of things that devalue their work. "Generate a rock song" is not a problem that working musicians have. "Take this riff I recorded with whatever guitar I have in the studio and show me what it sounds like as a Les Paul through a 5150 or…
I have used Music AI for what you describe, by uploading a track I have made myself and use diffusion on it with various genres, although I don't think that is the most interesting use case for Music AI.
Fusion is the most interesting use case IMHO.