Would it be possible (in theory) to build a receiver on an embedded platform, for instance an audio-only ESP32 speaker, or is there something in the protocol that requires a more powerful device?
https://gitlab.com/futo-org/fcast/-/wikis/Protocol-version-1
As you can see the 1.0 protocol is very lean and fits on an A4.
If you want to have an audio-only ESP32 speaker I don't see why it wouldn't be possible with the FCast protocol.