Spotify
A Raspberry Pi holds your account through Spotify's Web API and is the board's relay, so taps, skips and seeks go straight back to Spotify. It only resumes on the device you last played on, so a tap can't start music in somebody else's room. Premium needed.
No Pi? A Mac's Spotify app works too, read through AppleScript, no keys. Display only.
Sonos
No account, no keys. The Pi finds your speakers on the network and follows a room. Swipe down for the menu: pick a group, set its volume. Regroup in the Sonos app and it still knows which room you meant.
The volume slider is square-law, because nobody plays a speaker at 70.
Anything, really
Platter is a Resident app on an open ESP32-S3 panel. Push it a different Lua app and it's a clock, a weather flame, a usage meter. Try one on Bench before it touches the board.
Bench gallery