With drivers newer than 577.00, there will be CTDs if MSFS is running in DX11 - even without the Nvidia app.
If you want to use the latest Nvidia drivers starting from version 580.88, DX12 must be selected in MSFS 2020 settings.
If you use driver version 577.00 or older and want to play DX11 in MSFS 2020, the Nvidia app should not be installed.
Source https://forums.flightsimulator.com/t/msfs-2020-ctd-during-loading-with-or-without-nvidia-app-installed-dx11/732584/67?u=tenpatrol
Below is a step-by-step guide on how to uninstall and reinstall the NVIDIA driver.
Uninstall Nvidia driver using the DDU program in Windows Safe Mode.
1 Download Nvidia driver 577.00
2 Download and install DDU
Download Display Driver Uninstaller (DDU) Official | Wagnardsoft
Display Driver Uninstaller (DDU) is a driver removal utility that can help you completely uninstall AMD/NVIDIA/INTEL graphics card drivers and packages from your system, trying to remove all leftovers (including registry keys, folders and files,…
3 Unistall Nvidia driver using DDU in Windows Safe Mode.
How to use Display Driver Uninstaller (DDU) Guide / Tutorial | Wagnardsoft
4 Restart PC
5 Install Nvidia driver without Nvidia HD Audio and Nvidia app.
6 Restart PC