Unfortunately no write-up. But to get music to pause when the phone rings I use the Spotify integration and HA companion app. It's a pretty simple automation - it has one trigger when "Phone state" changes to "ringing", one condition that Spotify is playing, and one action which sets Spotify to paused.

I think the "ringing" state provided by the companion app only works on Android, not iOS though.

OwnTone has an HA integration so I would expect you can do something similar with that.