@dievanessa Permissions are requested by the operating system when you first try and do something you haven't done before, for example install new software that requires access to a folder in the Documents folder (like Sims 4 requires access to the Documents folder to create Electronic Arts and Sims 4 folders), or plug in a USB drive, or access files and folders in a restricted directory on the Mac. If your game is installed on an external drive the OS would prompt for permission for Origin to access the drive.
During the installation process you will have received these prompts and asked whether you wanted to allow access or deny. If you denied the game access to the Documents folder it cannot create the Electronic Arts and subsequent Sims 4 folder so cannot successfully load.
Go into System Preferences > Security & Privacy > Full Disk Access and make sure Origin has access.
Go into System Preferences > Security & Privacy > Files & Folders and make sure Sims 4 has access to your Documents folder.
