Since this Question is appearing in High Sierra macOS 10.13, one must assume the computer is running a minimum of Catalina and above in order to have the Apple TV app
What happened to iTunes? - Apple Support (CA)
Q - " The techs at Apple are baffled. The last thing to do is to delete and reinstall the app. "
A - The delete and re-install the Apple TV Application can not be done Sealed Key Protection (SKP) The Operating system in Catalina resides in a READ ONLY Volume
A - In Big Sur and Monterey the same Volume has been further protected form Third Party Software or User modifying, altering, removing or attempting to do any of the previously mentioned actions.
A - Any of my Apple TV movies / Show seem the coming in as MPEG-4 video file
HSL File type https://www.filesuffix.com/en/extension/hsl