I've had multiple issues with the game for a bit, but nothing game breaking.
Now, screen is locked on the starting green screen with the AC-logo. I've tried re-installing the game without success, and removed the instant game respons on my TV thinking that could've been the issues. What to do?
Hello @k-frondelius! Welcome to the forums 
I'm sorry to hear that you're encountering technical issues whilst playing Assassin's Creed Valhalla on Xbox Series S. Thanks for letting us know what troubleshooting steps you've tried already!
Would you be able to try the other steps shared on this console troubleshooting support article, as these steps help to combat a number of common causes behind technical issues in-game. These steps also provide us with a great starting point for any additional investigation that may be needed!
If you're still experiencing crashes after trying these steps, would you be able to let us know if you've been experiencing any flickering graphics at all? Or if it's only the freeze on the starting screen you've been encountering?
Thanks! 
devtrackers.gg