I too have the same issue as the OP. I am running an RTX 3090Ti with the Reverb G2 and have run the same VR settings in DCS for years. I do notice the stats in dcs fps window (CPU Bound Rendering) flashing yellow to red like a very fast strobe when the stuttering occurs. This is happening in all aspects of flight. Even sitting at the mission select role screen. Lowering settings does not work.
Edit:
Just checked the Task Manager Resource Monitor and see that CPU 2 and CPU 7 are pegged at 100%. CPU 6,5 &4 and pegged at 90%. CPU 1 is around 40-50% and CPU 3 is running the lowest around 30-40%. Just an observation on an i7 9700k 64GB Ram machine.