I could not resist to solve the issue. You brought me too close to the solution. ;-) Actually it has been a permission issue of Windows 10's "Temp" folder. I had changed the system environment variables from the standard path to "C:\Temp" that I had manually created. However, this folder "C:\Temp" was missing "full control" permissions for the "Creator Owner" group. By adding those permissions the XPS printer queue now works.