reinstall Apple TV MacOS app

Since you cannot actually delete the App, there is no way to re-install it.

If you removed it from the dock by mistake, look in the Applications folder in Finder for it, and drag it onto the dock again.

Otherwise, you will need to explain why you need to re-install it.

I assumed you deleted the app by accident, you can try going to the app store and searching for Apple TV or watch in safari at: http://tv.apple.com/

Why would one want to do that ? It is part of the Big Sur OS. ?

You would have to reinstall the OS.

Why do you need to reinstall the app?