

Last.fm is probably the closest thing functionality-wise to what you’re looking for as far as reccomendations go.
You can “scrobble” or log what you’ve listened to or enjoyed from a metric ton of sources, and reccomendations are based off the user community and tagging. Covers popular to underground and everything in between.
Not sure what the whole “federated” part of this adds to anything.













Initially connect when the target isn’t home, as a number of speakers make a distinct “startup” noise when a device connects.
After that, bear in mind that most bluetooth speakers have a small delay before they play audio, and this often means that the first second or so of audio will be cut off. Unless you use another app to keep a constant silent noise playing. The silence being sent as audio to play effectively “warms up” the speaker so the cut off portion is during the silence, not the actual noise you want. Some speakers need this silence to be infintessimally quiet static, as they’ll just drop pure silence. Pretty sure there’s an app on F-Droid for this.
You wouldn’t want your friend to only hear part of the chirp after all.
Also, most devices with a screen have a way to display the name of what device is connected. This especially applies to casting to screens. Name your phone something generic for safety.