I use Navidrome, and have set up Lidarr to feed it if I’m feeling a little hook-handed, if you get my meaning. Lidarr was a bit of a bollocks to set up, but once it’s running it’s pretty neat. I access it via Tailscale so can add stuff to the library wherever I am.

As for accessing it: again, I use Tailscale to run it through a reverse proxy on my website, so I connect to it using a subdomain. But as long as I’ve got Tailscale active on my phone, I could always access it that way. As others have suggested, I use Symfonium on my phone, and I use Feishin on everything else.

It all works pretty well, to the point that I don’t really use Apple Music anymore.