Thanks! My RFID project there is probably very over-complicated compared to a "proper" audio setup like you describe. Really all you would need is a Raspberry Pi to host a MQTT server and play a stream from Spotify (or similar). You could then use ESPHome as a simple RFID-to-MQTT reader, which would be extremely simple with ESPHome and is the kind of project that ESPHome makes beautifully and laughably simple!