@Audr3y16 There are a couple of things you can try, if you're still interested in experimenting. I don't know whether they'll help without uninstalling the Windows security update, but at the very least, it would be good to know that nothing worked.
Please set exceptions, in all antivirus/firewall programs you have installed, for both Origin.exe and TS4_64.exe. Please also set an exception in Controlled Folder Access (a feature of Windows Defender) for both. It should only be necessary to add TS4_64.exe, but might as well be thorough. Here's how to change Controlled Folder Access settings:
https://crinrict.com/blog/2019/03/windows-10-defender-controlled-folder-access.html
Please also remove your entire Sims 4 game folder from Documents\Electronic Arts while testing. A clean folder will spawn each time you launch the game, as long as it gets far enough. Be sure to delete this clean folder after each test.
In addition, temporarily disable OneDrive (no need to uninstall it) while testing. Here's how:
https://www.windowscentral.com/how-disable-or-uninstall-onedrive-windows-10
If these steps don't work, please try all of it again, this time adding another clean boot. Here are the same instructions as before:
https://www.windowscentral.com/how-clean-boot-windows-10
I understand how frustrating this must be, but the more information we have, the sooner we might find a solution. All we know right now is that some people with the security update can still play, and that uninstalling it doesn't help everyone. More information is always useful.