@sw33tpinkbabi The memory leak error is not uncommon in Sims 4 and doesn't typically cause the kinds of problems you've been seeing. I wouldn't worry about it.
Does switching back to DirectX 9 currently help? The option is with the other graphics settings.
Separately, as a test, try running Sims 4 on the Intel graphics chip. Performance will be significantly worse than it would be on the Nvidia GPU if the game were working properly, but it should still run fine on medium-high to high settings at 1080p, so you can get a sense of whether the problem is limited to when the game is using the Nvidia chip. Open Windows Settings > System > Display > Graphics settings, click Browse, choose TS4_Launcher_x64, and select the power-saving option. Do the same for TS4_DX9_x64 and TS4_x64.
You can see whether this worked by opening Config.log, inside Documents > Electronic Arts > The Sims 4, and scrolling down to Graphics device info. (Launch the game once after making any changes so that the file updates.) Whichever GPU is listed is the one the game was using when it loaded, at least. If you're still seeing the Nvidia card, right-click the desktop, select the Nvidia Control Panel, choose Manage 3D Settings > Global settings, and choose the Intel iGPU. This will affect all programs, so you'll want to undo the setting later, but it's a quick and easy way to test.
Running on the Intel chip, Sims 4 should default to DirectX 9 mode, which may not work well on the Intel chip for completely separate reasons. To force DX11 mode, open your EA App game library, click Sims 4 > Manage > View properties, and add -dx11 in the command line box.