There's already a huge library of royalty free music available and even just AIing some music up doesn't fully protect you from strikes if it hallucinates something close enough to an existing song.
Doesn't seem like much you could actually tweak beyond the short style queue and lyrics. To really be customizable you'd need a method to tweak the generation to inform the tone, inflection, and flow of the music at any given point to satisfy what you wanted to pair it with.
Songs have lulls and swells to go with the tone and emotion you're trying to create/communicate these are just strings of lyrics over boring barely connecting backing tracks.