So, I fly VR all the time, and this means I use much higher resolution, something to keep in mind. My approach is to simplify things. I have my VR headset (think monitor in your case) set to 100% native resolution, no super-sampling, no motion smoothing, just behaving like a simple high res monitor. My headset is set to 80hz, and OpenXR manages my frames at 40fps. So, if you have a 60hz monitor, set Vsync to 50% to target 30fps. Trust me, it will be smooth.
I have mostly Medium settings, with TAA and Render scaling from 150% to 200% depending on the airplane. This is very easy to adjust in the sim to match your airplane.
With this resolution, I get around 20ms GPU frame times with around 10ms CPU frame times. This means I am GPU bound. I aim for around 80% GPU load (40fps is 25ms frames * 0.8 = 20ms) to give me some headroom. I consume around 10 to 12 GB of VRAM depending on the aircraft.
Note that some "heavy" airfields like KSEA will pound your mainthread while you are on the ground. Lite airfields like CYYQ will not, so choose a lite field to test or test in the air.
Once you achieve this GPU bound state, you can experiment with the other settings.
I hope this helps.
4080S with Ryzen 9950x