Are you sure that all your Mods/CC are compatible with the latest patch? Sounds as if something is still conflicting with the game.
Try moving your entire Sims 4 folder to your Desktop and DO NOT DELETE IT!
Try creating a Sim and see if you can upload them to the Gallery.
@YoshiinoYoshi If you remove your entire TS4 game folder from Documents and launch the game, thereby spawning a clean folder, can you download gallery items into this new folder? If your own files don't work, try downloading someone else's, just to make sure there isn't a problem with your uploads specifically.
After that, the standard advice applies: Run the Origin reset tool for mac and generate another clean folder. If you can get things to function with a new folder, you can always move your existing files into it from your old game folder.
https://help.ea.com/en-us/help/origin/origin/how-to-reset-origin-on-mac/
By the way, when you originally removed your TS4 folder (when you got the game to work), what did you do with it? As long as you didn't delete it, you should still have all your old files, and you can move them into a clean folder as well.
