@Mimigaming15 Please do a clean uninstall and reinstall of Origin, as described here:
https://bluebellflora.com/how-to-uninstall-origin-on-a-mac/
If you have a third-party antivirus, disable it before reinstalling Origin, and don't reenable it until Sims 4 has installed.
If that doesn't help, do another clean uninstall of Origin, then create a new admin account on your Mac and install Origin into that. Try again to install Sims 4, and let Origin use the default install location, which should now be the user Applications folder of the new user account. You can move the game once it's installed; for now, just see whether it'll install in the first place.