You can also reduce the amount of information displayed in the HMD by pressing the HMD on the MFD, off the top of my head I believe it’s found in the SUPT menu, then toggling it between NORM, REJ1, and REJ2.
Edit: Found my old post about it.
https://forums.flightsimulator.com/t/does-hmd-work-in-vr/530734/4?u=raynen