@StevenSmith: Can you try heading to the Camera Cutout tab, and toggling off any apps you want to show in full screen? It may be the case that the 2 options are conflicting with one another, so any apps you've selected to hide the camera cutout can't be shown in full screen. Let me know if this helps.
I have the same problem. I only had two apps on the list for full screen/app default, but since I restarted the phone, I don't even have one app listed. And even when 2 apps were listed, they were only under the default list and had no tabs next to them. Were you able to get this problem resolved?
I have the same problem! I just got off a 2-hour chat with Samsung and they said "go to a service location and speak to a technician! I only have 5 apps listed under Aspect Ration and over 100 under Hide Camera. This is so frustrating! I even contacted the app developer for the app I am most interested in casting full screen. This is definitely a Samsung problem. I am just so glad to see I am not the only one. Thanks for posting.