@ElDimentio Try clearing Origin's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
and repairing the game: open your Origin game library, right-click on the Sims 4 icon, and select Repair. Even if you've repaired before, it might work better without Origin using stale cached data.
If that doesn't help, try disabling any apps that include an overlay, for example Steam or Discord. It shouldn't really make a difference, but some overlays conflict with each other or with the game. Disable Origin in-game as well: hover over your username, select Application Settings, then the Origin in-game header, and disable the option at the top.
If that doesn't help either, try playing in a clean boot:
https://www.windowscentral.com/how-clean-boot-windows-10
It would also be weird for this to make a difference, but given that I haven't seen other complaints about this, it does seem like something is going on with your particular computer.
The suggestion to plug the monitor into the graphics card is about overall system performance. Your GPU is capable of much more than Sims 4 could ever demand of it, especially on a 60 Hz monitor (even in QHD), so you probably wouldn't see any difference there. But it would help in other more demanding games.
