I use Volumio on a Raspberry Pi with a DAC HAT. The analog output goes to a whole-house distribution system. I installed the Volusonic plugin and it connects to my Navidrome server hosting the music collection. In this configuration, Volumio functions as a control plane. I do everything else (playlists, etc) from the Navidrome web interface. As a bonus, there are several Subsonic apps that work with Navidrome for mobile listening.
I tried Jellyfin, but never got it working the way I wanted. DLNA was particularly difficult. It would play two songs, then stop. I wrote it off as user error out of frustration, and moved to Navidrome. It’s been working well for me, so perhaps it’s worth trying since you already have Volumio up and running.
Note: The prominent comment at the Volusonic link claiming the plugin doesn’t work with Navidrome is over two years old and resolved. Don’t let that dissuade you from trying the plugin.
I use Navidrome with play:Sub (paid) or Amperfy (free as in beer) on iOS. I also use the Volusonic plugin with Volumio to play music throughout the house. All my music is curated using MusicBrainz Picard and the files are mounted read-only for Navidrome.
I looked at Roon briefly, and I know many people like it, but I can’t justify the cost. Plex and I don’t get along; pretty sure it’s operator error and/or grumpiness. Jellyfin looks promising, but I ran into challenges with it as well. I think if you’re just hosting music, then Navidrome is fine. If you think you might expand to series or films, something like Plex or Jellyfin could be better long term.