Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
For many months, there has not been a contract between Google and Roku for carrying the YouTube TV app. So, it's not available in the Channel Store. If the app is removed from your device, you may not be able to get it back.
Now, the next question is: was the device actually removed, or is this just some temporary glitch that's keeping it from showing?
If it's the latter, then it may show itself again. I've heard reports of the app temporarily disappearing.
If it's the former -- that can happen if the app is removed from any Roku device on your account -- then you're probably out of luck.
In either case, you can access YouTube TV from the YouTube app. Log in to YouTube on your Roku, then go to the YouTube TV link in the bottom left of the menu. If the YouTube TV app returns (a glitch temporarily making it not show), you can go back to the way things were. If the YouTube TV app was removed from one of your Roku devices, you'll have to keep launching from the YouTube app on Roku until Google and Roku reach an agreement to carry the app again.
DBDukes Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution." Note: I am not a Roku employee.