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, 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 that doesn't help, please list the platform you play on (Windows or macOS), and let me know whether OneDrive or iCloudDrive, respectively, is enabled.