I can't answer your original question but I have had a lot of success using Logitech Media Server (LMS) or PiCorePlayer (same thing but all in one, server and end player). They are also known as Squeezebox.
I ran a server on a pi, then ran the player part on more Pis including a pi zero w which had PCP installed (but I just used the player part of it).
Squeezebox used to be a Logitech brand, you can still find them on eBay. They closed it down, but open sourced it and it was taken over by the OS community.
It looks shit. But there is a Material theme you can add that makes it look far nicer. It will run your own media from the server, but also other services like TuneIn Radio, Spotify, YouTube, BBC radio...
I ended up with it because there is a plugin that allows Google Home Minis to be used as end devices and I have 3 of them. So I had 6 end devices (3 Google, 3 Pis) and I could run them all together playing the same music throughout the house.
It's a bit buggy sometimes, and it requires a fair bit of fiddling. I found that the Google devices would always be out of sync by a half second or so. But on the whole I loved it, and when my Dell Optiplex comes I intend to revive it on that.