Not exactly the setup you’re talking about but I use a series of raspberry pi’s each with these great little hifiberry amps and running Volumio software to achi

Not exactly the setup you’re talking about but I use a series of raspberry pi’s each with these great little hifiberry amps and running Volumio software to achieve whole house audio. There’s a plug-in called snapcast that allows for a server that streams audio to all the clients, keeping everything in sync. I control volumes of various rooms/zones through home assistant. Works really well for me.