I’m wondering how you got the Ultra Quality option for NVIDIA DLSS Super Resolution in MSFS 2020 - on my side the maximum I can select is Quality.
It looks like you’ve heavily modified the NVIDIA app settings - the screen flashing also suggests that, since I forced it on my side as well. I’m getting less flashing though, probably because I only have Quality as the maximum option and not Ultra Quality.
In the NVIDIA app, go to your profile for MSFS 2020 and disable Smooth Motion.
This feature is mainly intended for games that don’t support DLSS.