If you're technically inclined, self-host navidrome or jellyfin.
If you just want music and don't care about the streaming part, bandcamp (although it does have some basic streaming I believe.
If you want streaming and aren't technically inclined, Tidal.
Most of those are lesser evils compared to X, and that's probably the best you can hope for. And Bluesky is the obvious alternative lesser evil choice if you want a like for like replacement and aren't open to Mastodon.