the game keeps crashing after half an hour-ish of gameplay

The same is happening to me and it's not the first time.

Mine just did the same thing. No mods and everything is updated. I did buy the new expansion...not sure if that is the cause?

cattheunsuperior underduckie1 Elliecats  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.  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've moved but temporarily unread by the game.)  Don't add anything to the new folder yet; just start a new save and see how it runs.

If you get another crash, please provide a dxdiag.  Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop.  From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.