I first had the same problems with not getting access to the windowapp folder and could not use the dlss swapper with my Msfs store version. Then I learned the solution in a video: Move your msfs store version with the Xbox App on your computer(manage files option) to the xbox game ...
I get the popup (in MSFS), but I don't get any option for Frame Generation in the Graphics Settings. Not even grayed out. I have an Nvidia RTX 3090. EDIT: It was not mentioned anywhere but you have to turn on DX12 for Frame Generation to work. (You know what happens when you ...