Flickering screen with colored dots Xbox series X

@baz-e-baz Thanks for the video, to check have you tried the following?

• Clear Persistent Storage 
  • Go to settings > Select Device & Connections > Then Blue-Ray 
  • Select Persistent Storage > Clear Persistent Storage 

• Clear Alternate Mac: 
  • Go to settings > Select General  > Then Network settings 
  • Go to advanced settings > Alternate Mac address > Select clear 
  • Select restart 
• Delete local save
  • Press the Xbox button on your controller to open the guide, and then select My games & apps.
  • Highlight the game, press the Menu button on your controller, and then select Manage game & add-ons.
  • In the menu on the left side of the screen, scroll down to Saved Data, then highlight the saved data for your gamertag on the right and press the A button on your controller.
  • You'll be prompted to confirm deletion of this game save data:
  • Delete from console removes the local copy of this save. You can get it from the cloud the next time you play.
  • Delete everywhere removes your saved data from this console, the cloud, and all other consoles you play on.
  • Cancel leaves your data intact.