Hi there @1SmexyLoki can you check your account and console are properly linked? Instructions here:
https://help.ea.com/en/help/account/link-your-console-accounts/#how-to
I've seen other players affected by this on a different EA game that were advised to reset their password and also to go to profile.ea.com and see if you have the option to accept the terms and conditions there.
Also if you had all your save slots filled on an Xbox one that is unfortunately too much for your console with a game of this size, I was advised that by Xbox Support. I'd stick to a couple of save files instead. It's a lot for an Xbox one. Even on Xbox Series X I never exceed 3.
Your game version should be 2.1.6.2300. It can be found by selecting Sims 4 on your console home screen using the menu button (3 lines on it) and going to manage game and add-ons. You'll see the game version there. I'm adding an image of mine for you. That's just to make sure your game is up to date.
