Just as a reminder, I’m adding the link here where my solution is confirmed.
https://forums.flightsimulator.com/t/flashing-screen-with-nvida-dlss-frame-generation-on/738514/2?u=tenpatrol
As I mentioned before, if Smooth Motion is enabled, it can conflict with features like NVIDIA DLSS. Smooth Motion is mainly intended for games that don’t support DLSS, so when both are active, they’re not really compatible with each other. Turning Smooth Motion off is the correct fix in this case.