plaguebunny Is OneDrive running on your computer? If so, whether you deliberately use it or not, it could be interfering with Sims 4. So please try pausing syncing, which you can do by right-clicking the cloud icon in the lower-right corner of the screen, or perhaps hidden in the Tray (^ icon).
Additionally, if you used any content from the Gallery or your own library in the new save, please try again but without doing that. Create new sims and place them on a blank or default EA-made lot instead. And continue to test without any mods or custom content present.
If that doesn't help, please create a new admin Windows account and try playing there. Make it local, as in, don't link it to your Microsoft account or any email address; you'll be prompted to answer some security questions instead. You'll be able to launch Sims 4 without reinstalling anything, but your saves and other user data won't be available. That can be addressed later.