I run between 35-55 FPS with my system and a RTX 2070 Super. I also have never used more than 12GB of the 16GB system memory and about 7GB of the 8GB GPU memory. This is pushing two or three monitors and a 1080P projector.
This is according the the Developer's FPS count you can turn on via the Developer's task bar. The FPS counter also tells me that I am "mainthread" limited, which, if I understand correctly, is pretty much universal with all current CPUs. I am running at High settings as recommended by MSFS. I tried Ultra and using the 1920 x 1080 projector, I see very little difference, with exception of details further out, from the High settings.
So, my question is: Why would I want or need a larger more expensive GPS?