@katelynwstxoxo Please do everything together—clean boot, offline mode, disabling Online Social Features—but in a new admin Windows account. Make it local, as in, don't link it to your Microsoft account. You'll be able to launch Sims 4 without reinstalling anything but won't have access to your saves or other content. That's fine and is part of the purpose of this test, so don't transfer or download anything you normally use.
If that doesn't help, I'd like to see the results of some hardware monitoring. Please download hwinfo (it's free) from here:
https://www.hwinfo.com/download/
You don't need to install anything; just choose the Portable version, unzip it, and launch it from Downloads or wherever you like. If you do want the full installer, be sure to click the button for hwinfo itself, not for lansweeper.
Restart your computer, open hwinfo, choose Sensors Only, and click the button that's a sheet of paper with a + to start logging. Save the log file to your desktop for easy access. Wait five minutes, then open Sims 4 and play for at least 20 minutes. Don't alt-tab out of the game or run any other programs, aside from the EA App of course, while you're testing. When you're done, click the same button to stop the logging.
Please upload the log to the third-party filesharing site of your choice (Google Drive, Dropbox, etc.) and link it for me. Either leave it in .csv format or, if you're going to use OneDrive, create a .zip file, and don't open the log before uploading it, or else my log reader might not be able to interpret it.