Hello, I'm Louie, and I'm happy to help you today. Hope you're doing well and safe there. I'm sorry that you're having trouble with gamebar.
To Repair or Reset Xbox Game Bar on Windows 11:
Open Windows Settings > Apps > Apps & Features
Search for Xbox Search Bar in the Apps list
Click on Advanced Options
Here you can Reset or Repair the Xbox Game Bar.
You can reset the app via Settings > Apps> Xbox > Advanced settings > Reset.
I would also recommend you to try the solutions provided on the support article below.
https://support.xbox.com/en-US/help/games-apps/...
Hope this helps.
Kind regards,
Louie