nostr:npub1r0rs5q2gk0e3dk3nlc7gnu378ec6cnlenqp8a3cjhyzu6f8k5sgs4sq9ac has built one, works via blossom servers I believe?
nostr:npub1yfg0d955c2jrj2080ew7pa4xrtj7x7s7umt28wh0zurwmxgpyj9shwv6vg has a nostr sign in. I'm not sure if there is a native nostr music app that stores the audio on relays.
Discussion
You can’t store audio on relays, only events. But you can use blossom uploads.
I going to update Plume soon to direct people who want more from the music to go to your music player. My hope is that people will come across content producers they're interested in while scrolling on Plume then go to appropriate apps to enjoy their content with full expected functionality.