@x-Sakaeru-x Your dxdiag lists some generic Windows errors, so it's a good idea to run a couple of basic checks on your Windows system files:
- Hit Windows key-X
- Choose either “PowerShell (Administrator)” or “Windows Terminal (Administrator),” whichever option is offered
- Inside the window that appears, copy and paste “DISM.exe /Online /Cleanup-image /Restorehealth” without quotes, and enter
- The system will start validating soon. If it throws an error, please list it here
- After it reaches 100%, hit Windows key-X again
- Again, choose “PowerShell (Administrator)” or “Windows Terminal (Administrator)”
- Inside the window, copy and paste “sfc /scannow” without quotes, and enter
- Post the message you receive here
Restart your computer, hit Windows key-i, select Update & Security, and click the box to check for updates. If any install, restart again afterwards.
Please test Sims 3 in a clean user folder, if you haven't already. Move the entire Sims 3 folder out of Documents > Electronic Arts and onto your desktop, and when you launch the game, a clean folder will spawn with no content. (Your saves and other content will be intact in the fodler you've moved but temporarily not read by the game.) Don't add anything to the new folder yet; just start a new save in Sunset Valley and see how it runs.
If the new save runs fine, try copying over one of your existing saves, but nothing else yet. Since you're copying and pasting rather than dragging and dropping, you don't need to worry about the effects of missing mods and custom content.
If the new save is laggy too, please try playing in a clean boot:
https://support.microsoft.com/en-us/topic/how-to-perform-a-clean-boot-in-windows-da2f9573-6eec-00ad-2f8a-a97a1807f3dd
The one service you need to leave enabled is the EABackgroundService, which the EA App needs in order to run. Disable everything else, as described, and when you restart your computer, go through the Task Manager's background processes list shutting down everything that doesn't absolutely need to be running. If you accidentally kill the wrong service and it doesn't restart on its own, just reboot your computer again.