Can't start / delete games after moving them around via "Apps & Features"

I think you need to format eternal drives for games in a proprietary way. You do on the xbox anyway. My Guess is there is likely some hidden files on the original SSD that you didn't move to the external SSD?

Although you can't move the store or xbox app you can move the games. Click on start and then settings. Click on System and then apps & features. Find the games that you want to move and left click them. You'll have two options, move or uninstall. Click
on move and select a new destination, i.e your new SSD. You can do this for all your games, not just those that have been installed via the store or xbox app.

I don't recall any huge issues with the beta, personally. The biggest problem I had was that installed games would stay at "ready to install" after moving them around. Deleted them and re-downloaded and haven't had the problem since.

Most app-level issues in the beta (no audio from TV, games not starting) can be resolved by quitting the specific app and restarting it. Hard reboots are few and far between for me.

most if not all windows/xbox app games install to windowsapp folder, this is encrypted, if you took ownership or messed with the files then you have broken the encryption and will need to delete the folders and redownload the game. you can't just move windows games into different folders, you can move them to another drive via the apps and programs menu but they have to reside in the windows app folder that is created by the system.

Report them via Treyarch's report feature and move on. Save that game in your file share if you are especially concerned about it, then report them via message to MaTtKs. He won't mind.