@MysteryKoolAid7 Right, since the new account works, the issue is only on the main account, which is good news all by itself. First of all, if you use OneDrive in the main account, try pausing syncing before you try to launch Sims 4. Right-click the OneDrive icon in the lower-right corner of your screen, select Pause syncing, then 2 hours, and see whether you can play. If you can, it becomes a matter of adjusting OneDrive's settings.
If you don't use OneDrive, or pausing syncing doesn't help, try running the takeown command on the Documents folder in the main account. You're going to use this command:
takeown /F "C:\Users\username\Documents"
Write your actual username for this Windows account (your main one) instead of username. Since the syntax needs to be exactly right, please copy this command to a Notepad file, substitute in your username, and then copy that string when you're ready to use it. Hit Windows key-X and choose either "PowerShell (Administrator)" or "Windows Terminal (Administrator)," whichever option is offered, paste the command into the window, and enter.
Then restart your computer and try again to play.