When you allow an App to access Bluetooth, they can create a bluetooth connection. This does not use the pairing process and the one I would suspect is Google Home. The protocol they use for the Bluetooth connections is BLE and those are not removed from the Bluetooth settings page by tapping the blue info button, they are removed from the App that allowed the connection and in your case that would be Google Home. You may be able to review the previous devices that Google Home used in the app or settings for the app. It would be listed under Devices.
Users who bought a Tesla were concerned when they noticed strange alphanumeric devices showing connected in Bluetooth Settings and they were unable to remove them, but then they realized that the connection was the Tesla and it was the Tesla app that allowed it to be connected to their phone.
Spotify uses BLE for connections to speakers for audio output and you connect those speakers in the Spotify app, not by pairing in Bluetooth. I am not aware of Spotify using another phone as a speaker though. It may have identified a Google speaker as a phone, but I have seen no evidence that would be the case. Just revoke the Bluetooth permission unless you do connect to a speaker when using the app.
Since you no longer use the Google Home app, then delete it and turn Bluetooth back on. I suspect you will not see that appear in your Settings again and if you do, then come back here immediately so we can figure this out for you.