Mastodon: @RmDebArc_5@toot.io
Jellyfin is quite capable for music, however Navidrome has a much better client ecosystem. Personally I use the Finamp beta on mobile as it does everything I want and is quite stable, but if you want Android auto/apple carplay you will have to use a client that isn’t as reliable or proprietary (paid.
Stremio Youtube
You can use pretty much anything you can with desktop Linux, however some apps may not work with a controller