Bug WINDOWS_UWP && UNITY_XR_WINDOWSMR not working?

In my Application I want to scan a QR Code and spawn a Panel on top of it but I have 2 problems with the process..

First of I use Unity 2021 with MRTK3 pre 12 and the QR tracking code is from here:
MixedReality-QRCode-Sample/SpatialGraphNode.cs at main · microsoft/MixedReality-QRCode-Sample · GitHub

Here is how I changed it:

Code (CSharp):

1. if (node == null)
2.             {
3.                 Debug.Log("InitializeSpatialGraphNode");
4.                 node = (Id != System.Guid.Empty) ? SpatialGraphNode.FromStaticNodeId(Id) : null;
5.                 if (node != null)
6.                 {
7.                     Debug.Log("Initialize SpatialGraphNode Id= " + Id);
8.                     isNew = true;
9.                 }
10.             }
11.  
12.             if (node != null)
13.             {
14.                 if (node.TryLocate(out Pose pose))
15.                 {
16.                     // If there is a parent to the camera that means we are using teleport and we should not apply the teleport
17.                     // to these objects so apply the inverse
18.                     if (Camera.main.transform.parent != null)
19.                     {
20.                         Debug.Log("Pose before transformedby QRPose = " + pose.position.ToString("F7") + " QRRot = " + pose.rotation.ToString("F7"));
21.                         pose = pose.GetTransformedBy(Camera.main.transform.parent);
22.  
23.                         // Rotate the panel so it faces the user
24.                         pose.rotation *= Quaternion.Euler(180, 0, 0);
25.                     }
26.  
27.                     if (isNew)
28.                     {
29.                         isNew = false;
30.                         gameObject.transform.SetPositionAndRotation(pose.position, pose.rotation);
31.                     }
32.                     Debug.Log("Id= " + Id + " QRPose = " + pose.position.ToString("F7") + " QRRot = " + pose.rotation.ToString("F7"));
33.                 }
34.                 else
35.                 {
36.                     Debug.LogWarning("Cannot locate " + Id);
37.                 }
38.             }

When I scan the QR Code my Panel with the SpacialGraphNode Script get spawned in (but always facing away from me? I don't know why but that's why the 180° rotation is in there) but it never gets a note so it can't position my panel. Adding some Debug texts reveals that I always end in the #else path wich just returns null all the time.

If I change the #if WINDOWS_UWP && UNITY_XR_WINDOWSMR to just #if WINDOWS_UWP and switch to player I can see that the code should be reached but then I get an error saying that "WindowsMREnvironment" is not in "UnityEngine.XR.WindowsMR" maybe that is the problem?

I tried running the App through Holographic Remoting and also building it and starting the app on the HoloLens itself. Has anybody an idea what the problem could be?


Best regards