Sims is totally bugged

43TBH  That's good in that it means the problem is limited to your old save, not a general system issue.  For the old save, try moving your main household to a default EA-made lot, or to a blank one.  Don't place a house from the Gallery or your own Library; just build a box and put their stuff inside if you have to.  You don't need to save your progress either; this is just for testing.

If this doesn't help, empty out your sims' inventories, and the household inventory, and items (fridges, bookcases, etc.) that have their own inventories, in that order.

Thanks Puzzle! My New save wasn't affected. What does that mean for my previous one?

43TBH  Please test a different household in the same save (you don't need to save your progress), and a fresh sim or sims in a new save, for comparison's sake.

If the new save is affected, provide a dxdiag.  Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop.  From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.

For the message about deleting items, that's likely coming from OneDrive.  If you'd like to get rid of it, or at least keep it away from your Sims 4 data, please choose the relevant option here:

[CURRENT ISSUE] Sims 4 saves/user content disappearing (PC) | EA Forums - 11838402

Some of that thread won't apply to you, but the OneDrive settings are the same.