I Found this interview to Doja Cat, which explains what I would like to create through RemixerApp.  

She used to download instrumentals from youtube and play with them to create music.

users could get the track they want from a song (voice, drums, chords, etc) and use that.  All this while getting discoverability by referencing the artist and sharing royalties in case the remix gets popularized.

And I think web3 can really enable this kind of intertwine between content, ownership (provenance) and value (royalties).
https://youtu.be/xuMuNJ4_g10?t=317
 

Fabulous!   This is exactly what I was looking for!