I tried to use Nvidia Control Panel to set my nvidia graphics card as default for sims 4. The problem is that the option to do this (select graphics processor for this program) is missing. The control panel should look like this:
You can enable a tray icon the Nvidia Control Panel to show all applications using the dedicated GPU. Open Nvidia Control Panel... Check ✓ Display GPU Activity Icon in Notification Area
Bottom-right corner windows desktop display tray looks like this: ^ When you have to game running, look for the rainbow icon. Left-click to show all applications using the GPU.
If you see The Sims 4 listed, the laptop is using the dedicated graphics card correctly. There shouldn't be any reason to disable the integrated graphics chip. Laptops with both an integrated chip and a dedicated card will switch between the two as needed to save on battery + resources. When launching programs such as games, then the dedicated card is put to use. Sometimes this does require opening up Nvidia Control panel making sure it's set to use the dedicated card as you've already done.
I wouldn't worry about how the Control Panel appears for someone else. Different drivers / graphics cards can affect how the Nvidia control panel appears. I promise if the game is showing up in that tray notification, this means the correct GPU (which would be your RTX 2080) is in use.
I've not had any issues but since I did pay for the NVIDIA graphics card I wanted to make sure that's the one my computer is using. And I do now want to know why the option isn't there because it should be. Here's my dxdiag report.