@mustardmaximum As a test, please try playing in a clean user folder. Move the entire Sims 4 folder out of Documents > Electronic Arts and onto your desktop, and when you launch the game, if it launches, a clean folder will spawn with no content. (Your saves and other content will be intact in the folder you moved but temporarily not read by the game.) Don't add anything to the new folder yet; just let me know whether you can get far enough to start a new save and play in live mode for a bit.
If you get the same error, and you use a third-party antivirus, try disabling it, temporarily, and repairing the game. Open your Steam library, right-click the Sims 4 icon, and select Properties > Local files > Verify integrity of the game files.
If that doesn't help, or you don't use a third-party antivirus, please reinstall the game again (sorry), but this time, use a different location. Create a new Steam library:
https://help.steampowered.com/en/faqs/view/4BD4-4528-6B2E-8327#default
Create the folder on the root level of whatever drive you want to use. For example, C:\Games is fine, but not C:\Program Files\Games. Install into that folder. If you do have an antivirus installed, disable it while installing Sims 4, and don't reenable it until you've tested the game. As long as you don't do anything else at the same time, your ocmputer should be safe.
