I used a generative AI music tool to create ~1 minute snippets of fully mixed music. The tool offers 2 fields: Lyrics and a style prompt. From the initial audio you can generate continuations from them, creating different branches and there's some syntax to specify structure too ([chorus], [verse], [outro], (instrumental) etc). The quality of the compositions is quite good, though the choices it makes can be rather random just like any generative AI but that isn't always unwelcome.
From there I picked the best and most interesting bits of audio, split them apart those apart into separate tracks (vocals, guitar, percussion) with another AI. At that point I can bring them into a music sequencer, pull them apart, time stretch, rearrange, anything. You can generate an instrumental with a lead guitar, pull it out and sprinkle it through the entire song. Re-spin vocal deliveries, mix and match them.
This is a draft of something I've been working on: https://voca.ro/15yurCvoA9yR
The main drawback is the quality, it's like a mediocre cassette tape recording much of the time and splitting it up into tracks causes some generation loss.