I just set it up e2e on Ring last week. It generates the a key and a word list (for backup) on your phone. You have to physically be in vicinity of the Ring camera to activate encryption on the camera. My impression is that Ring is truly offering a version of video collection which they can't access.

But I think your third point is valid, there is nothing stopping Ring from telling the app to share a user's keys and then give them to whoever is asking.