There’re several possibilities, actually. It’s basically the same way I do it in P3D by using overlays in your VR.
If you’re using standalone WMR, go to the cliff house before launching MSFS and click on the Desktop application. Make the window to follow you (icon on the upper right corner of the window) and disable “switch desktop automatically” on the bottom right. When switching on VR in MSFS, the desktop window should be visible for you in VR.
The second option, and the by far most sophisticated one, is to use SteamVR for WMR and purchase the Steam app OVR Toolkit. It will let you show whole desktops and/or individual programs (like vPilot) in VR, and you can resize and place the windows around you in whichever way you want (NB: You need to change a parameter in its config files to show the mouse cursor on these windows, but I can elaborate on this later if requested). You can even let it hide the windows when you’re not directly looking at them, so that the immersion in the cockpit doesn’t suffer.
I’m a bit surprised that it works right out of the box also in OpenXR, as I was under the impression that it’s limited to OpenVR for now. This little tool has a great support, weekly updates and is the best thing ever for a VR pilot. I myself mirror my old MacBook in VR and have all the information (like flight plan, check lists, weather, etc.) right there with me.