Android TV's built in daydream doesn't have the options for you to choose personal photos (from Google Photo). I tried another daydream app from Google Play, but the one I tried adds black bars to fill in the screen, whereas I preferred the "blurred photo" background from Chromecast.
Has anyone found an identical replacement or workaround?
Have you tried the Google Home app? The last I checked it allowed you to configure ATV devices although not quite as much as a Chromecast.