Please run the Origin reset tool and see if that fixes it.
The game should be installed on your Mac somewhere, it isn’t stored within Origin. The Origin in your Downloads folder will be just that, the .dmg download. When you launch Origin it loads the app from your Applications folder.
Please open Terminal and copy and paste the following search command then hit Enter/Return:
find / -type d -name "*The Sims 4*" 2>/dev/null
After a little while it will return the results of the search. Please copy and paste the results in a post here.
The Electronic Arts folder that contains your saves etc. should be in your Documents folder. It’s useless in the Downloads folder and is never created there by the game. Do you use your Downloads folder as a repository for all your data?
