When I play big team heavies on matchmaking the game freezes like after 2 games and then the Xbox shuts off.
As this appears to be an issue with your game, we recommend heading over to https://aka.ms/HaloSupport for further assistance. Please review the latest known issues and submit a ticket if your issue is not listed.
Thanks!
2 things ive found that help is to have skins off. Also, reboot the game after every match. I know that sounds annoying but its better than getting slapped with a 5,15, 30 min ban because the game crashed.