I have the most current updates on all my devices. I have set my photos up as an ATV screensaver for years, know the steps, i,e. Using iTunes, etc. I have a 4th gen ATV and it sets up fine and my photos begin to display at the appropriate time. I go thru the same steps with my ATV 4K, it lets me go thru all the steps and yet reverts back to aerial both in the settings and the display. Any ideas how to fix?