Hi there!
I just purchased a Quest 3 headset 1 week ago and yesterday I downloaded Vorpx.
I was able to get Arma 3 running and play online with my friend but I had significant problems with the HUD and mouse controls. I think the vorpx hotkeys and menus are interfering.
Hitting the middle mouse button should activate Aim Down Sights but instead it switches between VR display modes. Could not figure out how to turn this off.
I was unable to access the action menu while in game.
Also while in the menus the displayed mouse cursor was unable to reach certain buttons on the screen, running out of room to scroll, as the cursor position was out of alignment with the movement.
I was playing around with getting a custom resolution set up to match the native resolution of the Quest 3 so that might have messed things up.