How to fix errors occurring with Task (.Net) and thread (WPF)?

Achieved Goal:

I am considering using PowerShell to monitor the input video from a USB camera device in real-time.

Problem:

Problem 1: When using the await class to wait for the return value (__ComObject) of the .Net async function, the first call (InitializeAsync) passes, but an unknown error occurs on the second call (StartPreviewAsync).

Problem 2: If I proceed without waiting for the above StartPreviewAsync, a thread error occurs.

Error Messages:

Error 1:

Exception occurred while calling "Wait" with "0" arguments: "One or more errors occurred."

Error 2:

Exception occurred while calling ".ctor" with "0" arguments: "The application called an interface that was marshaled for a different thread. (Exception from HRESULT: 0x8001010E (RPC_E_WRONG_THREAD))"

Additional Information:

Changed the execution of $ui.Content = [CaptureElement]::new() to be executed within the UI dispatcher invoke, but it had no effect.

# using namespace
using namespace System.Windows
using namespace Windows.Foundation
using namespace Windows.Media.Capture
using namespace Windows.UI.Xaml.Controls

# using dotnet
using assembly  PresentationFramework
using assembly  System.Runtime.WindowsRuntime

# import Runtime type [TypeName, AssemblyName, ContentType]
[Windows.Foundation.IAsyncAction,         Windows.Foundation,       ContentType=WindowsRuntime]
[Windows.Media.Capture.MediaCapture,      Windows.Media.Capture,    ContentType=WindowsRuntime]
[Windows.UI.Xaml.Controls.CaptureElement, Windows.UI.Xaml.Controls, ContentType=WindowsRuntime]

# init MediaCapture
$capture = [Mediacapture]::new()
[await]::Action($capture.InitializeAsync(), [object])

 # ui
$ui = [Window]::new()
$ui.Dispatcher.Invoke([Action]{
    $ui.Content = [CaptureElement]::new()
    $ui.Content.Source = $capture
    [await]::Action($capture.StartPreviewAsync(), [object])
})
$ui.ShowDialog()

# awaiter class
class await{
    static [object]Action([__ComObject]$async, [type]$type){
        $asTask  = [WindowsRuntimeSystemExtensions].GetMethod("AsTask", [IAsyncAction])
        $netTask = $asTask.Invoke($null, @($async))
        $netTask.Wait()
        return $netTask.Result
    }
}