I am having the exact same issue and it seems to be pretty rare as you're the only one I've found experiencing this same thing! So frustrating, I'm trying all the troubleshooting steps I can.
@Gregology Try playing in windowed mode. If you can't switch in-game, open Options.ini (in Documents > Electronic Arts > The Sims 4), search for fullscreen , and set it to 0 (zero).
I'm playing in windowed mode after a clean boot, literally every disabled that can be disabled, and still having the issue - tested on both modded and non-modded saves and still having the same issue, unfortunately.
@Gregology Please run a dxdiag and attach it to a post.
https://help.ea.com/en-us/help/pc/how-to-gather-dxdiag-information/
