I listen to Paul and Brad on their First Ring Daily podcast, and of late there has been discussion of hardware for playing music in a fashion similar to Sonos. I tried this a long time ago when I bought into Slim Devices before they were taken over (and then ruined) by Logitech. I haven’t tried to solve the problem since, but I am vaguely aware there is a lower cost solution to the problem involving RPi’s or similar.
https://volumio.org/volumio-overview/
And if you just want to solve it and not built it too, you can use [lots] of money to solve the problem with:
Personally, I think I’d try using a $60 bit of kit ($30 for computer and $15 for the DAC and $15 for case and power supply):
https://wiki.pine64.org/index.php/Pine_A64_Software_Release#Volumio_Digital_Audio_Player
https://store.pine64.org/?product=pine-a64-board-2gb
https://store.pine64.org/?product=pine64-stereo-audio-dac-pot-board
https://store.pine64.org/?product=pine64-acrylic-open-enclosure
https://store.pine64.org/?product=pine-a64-usa-power-supply
I’m sure other’s here may have other suggestions also… This approach doesn’t include any powered speakers. Is there an open source powered speaker that competes with Sonos?