Apple TV HD, tvOS 11
tvOS 11 is 2017–2018 era, so it seems updates have been skipped for a long time. The recommended version as of today is the current tvOS 15.1.1.
The current version of the YouTube app is indeed listed as requiring tvOS 12.0 or later.
Tried the apple remote nothing.
If the Siri Remote isn’t responding, then it may have lost its pairing. Try pairing again. If your Apple TV remote isn't working - Apple Support
the apple tv doent work
What does that mean? Does it produce any visuals at all? Is the status light glowing?
If your Apple TV doesn't turn on - Apple Support
If the update issue persists, and doesn’t complete successfully, then try restoring through a computer. Restore your Apple TV - Apple Support
If even that doesn’t work, or if you don’t have what you need to connect, make a reservation at a Genius Bar or contact an Apple Authorized Service Provider.