I just recently built a 9900K+2080ti+32Gram+1T M.2 computer.
Since the release of MSFS2020, I have been studying how to optimize FPS performance to get the highest.
I am not using 4K.
Use 208 and DA62withG1000 (turn off enhanced PFD terrain display) test
Default big city 30-40FPS
30-38FPS for big cities with addon
Village small airport 60FPS
Town + addon airport 47FPS
City + addon airport 38-47FPS
Use A320, B787, all FPS 40% OFF
MSFS2020 should be called satellite map simulation 2020
Performance problems may require DX12 to solve.