I couldn’t see if it would work with chromecast audio. I have a few chromecast audios for in-sync music source to old school 70’s receivers and speakers in a couple different rooms, as well as modern iPhone dock / speaker eg in the kitchen that have a line in.

Whatever app I use to play music needs to support chromecast audio.

I think Plex could do it but I haven’t bothered to run my own Plex server for ages.

What alternatives to Spotify for self hosting are there that support chromecast audio, or what alternatives to chromecast audio are there, given they are discontinued