looloolooweez If the Config.log file lists your Nvidia GPU, that's the GPU the game is using at startup (when the file is updated), and it should also determine what version of DirectX the game uses. Are you sure you haven't added -dx9 as a command line argument in the EA App? It would be under Sims 4 > Manage > View properties. And that would override the game's default behavior.
If you'd like to force DX11 mode, add -dx11 as a command line argument instead.
I see you've posted in the DirectX 11 thread on Answers HQ as well, which is the thread EA is monitoring. So let's continue there if you have further questions.