I assume you have an Oculus headset or similar, not WMR, as at Oculus it indeed works this way. A Reverb G2 for example needs you to start WMR first though. I use a batch file too if I want to fly in VR, starting WMR first, then running a 5 second timer to let it stabilize and then launch the sim.
The curse of running a Microsoft app together with a Microsoft app in a Microsoft OS… This never works well.