@ZoeMazeyrac To force-quit Origin, press command-option-esc, and choose Origin from the list of open apps. Do the same for TS4. If all else fails, you can hold down the power button on your mac until it shuts off. This is not great for the computer in general, but it sounds like you don't have a whole lot of options.
In the future, don't try to do anything to your game while it's running. If you have to force-quit first, fine, but make sure it's closed.
Before opening Origin again, run the Origin reset tool for macs.
https://help.ea.com/en-us/help/origin/origin/how-to-reset-origin-on-mac/
Then disable Origin in-game: Hover over your username in the lower left corner, select Application Settings, and look for the Origin in-game tab.
Next, drag your entire TS4 game folder out of Documents and onto your desktop. When you launch the game again, a clean folder will spawn with no content. Make sure you can start a new save in this clean folder, and then we can worry about adding mods or custom content.