@ExeRay In the rtss settings try enabling passive waiting and or try the other sync modes. Also make sure application detection in the main rtss window is set to high. You can change them all while flying, no restarts needed. They might help smooth things out for you. This stuff can be very system specific, so worth trying all options.
DX12 has always performed better for me in VR on both 3090 and 4090. DX11 seems to get hung up on quick camera panning and rapid manoeuvres while 12 remains smooth. It does chew through vram though.
I really miss the SU10 beta 1 DX12 work Asobo did and then quickly removed. For a brief period it felt like they had unleashed the real sim. It’s never been that good since.
The sun/shadow bug I mentioned is this…
Affects both 2D and VR in DX11. It actually still happens in 12 but with only about 10% of the intensity, usually the bug is short enough to pass between frames without causing a stutter there. Super annoying in 11 though.