JimmyH:tkr001:Or build your own using a nuc in a fanless case and install Rock. Way cheaper and IMHO just as good.
I'm not familiar with Rock. What does it do and how well does it work?
I'm getting interested in this area at the moment, as not that I'm close to finishing sorting out my TV and movie server, reorganising the way I manage my music and stream it around the house is getting to the top of the project list. Both Plex and Jellyfin, which are excellent for films and TV shows, seem to have deficiencies as music servers.
At the moment I have a bunch of Panasonic Allplay speakers, and three Chromecast Audios, which I use for music streaming. I'm hoping to keep those in service, and overhaul the backend (which currently uses Jellyfin and DLNA, and isn't satisfactory).
Have you experimented with Plexamp? It seems to solve a lot of the Plex music problems. You do need a Plex pass sub though.