The YoutubeTV app disappeared, but I can still access it through search function and the regular youtube app. I have done updates and restart thru the menu process to no avail. It seemed fixed after having issues last night only to wake up and find the app completly gone and I am also unable to uninstall the app because of this.
On your Roku remote, try pressing Home 3x, Up 2x, then left, right, left, right, left.
Scroll down and see if you can remove it from the list.
Then restart your Roku device and try to reinstall it from the Search feature on your Roku device.
If the method suggested by @AvsGunnar does!'t remove the installed channel, try the official Roku remote app on an Android/iOS phone/tablet connected to one of the Rokus on your account to remove the channel from your account. At the bottom of the app's Home screen, click Search and do a search for the installed channel name. If it's able to find the channel, on the resulting screen you should get options to Launch the channel on your Roku, or Remove the channel.