Hopefully a useful comparison for you:
I’m getting 45 fps on takeoff at OMDB with the A310 and traffic/AI/MP on.
System is a 5900x and 3090, so what should be a slower CPU and GPU.
Settings are pretty much all Ultra, 4k@90% render scale, DX11 TAA, and 150 TLOD.
So if you’re dropping below 20 I think there’s definitely an issue or some major tweaking to do. Good luck!