Have a project set to the UWP platform with the xr.sdk.openxr package installed.

Set OpenXR as the active loader and set "Initialize XR on startup" to false.

Test:
Developer should be able to start subsystems and initialize uwp app into vr mode during runtime.

Result:
Errors appear in console and app does't change.
See attached InitDuringRuntime.txt

Expected:
No errors appear and app enables vr

User mentions potentially doing this here:
[https://forum.unity.com/threads/openxr-plugin-tries-to-start-vr-even-if-initialize-on-startup-is-set-to-false-uwp.1408345/]

Basic code to start/stop subsystems:
{quote}~{color:#172b4d}public static void StartSubsystems(){color}~
~{color:#172b4d}{{color}~
    ~{color:#172b4d}var manager = XRGeneralSettings.Instance.Manager;{color}{color:#172b4d}   
     manager.InitializeLoaderSync();{color}~
    ~{color:#172b4d}manager.StartSubsystems();{color}~
}

public static void StopSubsystems()~
~{color:#172b4d}{{color}~
    ~{color:#172b4d}var manager = XRGeneralSettings.Instance.Manager;{color}~
    ~{color:#172b4d}manager.DeinitializeLoader();{color}~
    ~{color:#172b4d}manager.StopSubsystems();{color}~
~}~
{quote}