Question Custom XR provider with Unity XR SDK. headless mode needed.

Hello!
I'm creating my own own XR provider using the Unity XR SDK.

Currently I'm rendering to shared textures and passing them to a custom compositor and using BlitToMirrorViewRenderTarget function to copy a mirrored view of the game to the main Unity Game Window. The compositor (custom) is responsible for creating a separate window that renders to the AR Device (custom).

Would like to know if it's possible, and if so, how to implement a "headless" Unity game, that still renders to the shared textures and submits them to compositor, but doesn't create a window itself. The Mirror view then would be handled by the compositor.

Tried:
* setting the build as *Server Build* (Unity 2019.3.0f1)
The game successfully registers the custom providers and loads the subsystems. But crashes when asked to make render targets. My guess would be that in this case Unity does not initialize a graphics device.

* running the build with -batchmode flag. Looking at the log file it would seem that Unity is running without problems but in reality what happens is Unity creates and empty Window (nothing renders to it) and the compositor window is missing.

Don't have other AR/VR devices to test how are existing XR Plugin Providers working.

Building for Windows Standalone