Is this with TAA and MSFS render scale 100 or DLSS Quality because if the former then that is likely your problem? Try DLSS Quality at OXR 150 and if that gives you good results you should try higher OXR to find the right balance of visual quality versus performance.
For reference, I get about 40 FPS average, even at complex airports with complex aircraft and lots of AI and MP traffic, with my 5800X3D / 4080 / 32GB DDR4 3200 / Reverb G2 and the following settings, so you should be doing much better than this with your system:
