herbalbrewedtea Please try playing in a clean user folder. Move the entire Sims 3 folder out of Documents > Electronic Arts and onto your desktop. When you launch the game, a clean folder will spawn with no content. (Your saves and other content will be intact in the folder you've moved but temporarily unread by the game.) Don't add anything to the new folder yet; just start a new save and see how it runs, that is if you can get that far.
If you see iCloud Drive redownloading your folder, or restoring it to its previous location, or anything weird like that, let me know.
If you don't see that but the above doesn't help, please try again, except with your computer offline. You can sign into the EA App and put it in offline mode, then disable wifi before pressing Play.