Example of trying to register a Windows RT event via PowerShell, specifically here we're looking at events on Toast Notifications

Toast-RTEvent-Example.ps1

$XmlString = @"
<toast>
  <visual>
    <binding template="ToastGeneric">
      <text>Default Notification</text>
      <image src="C:\Program Files\PowerShell\7\assets\Powershell_av_colors.ico" placement="appLogoOverride" />
    </binding>
  </visual>
  <audio src="ms-winsoundevent:Notification.Default" />
</toast>
"@

$AppId = 'Microsoft.AutoGenerated.{A49227EA-5AF0-D494-A3F1-0918A278ED71}'

$null = [Windows.UI.Notifications.ToastNotificationManager, Windows.UI.Notifications, ContentType = WindowsRuntime]
$null = [Windows.Data.Xml.Dom.XmlDocument, Windows.Data.Xml.Dom.XmlDocument, ContentType = WindowsRuntime]

$ToastXml = [Windows.Data.Xml.Dom.XmlDocument]::new()

$ToastXml.LoadXml($XmlString)

$Toast = [Windows.UI.Notifications.ToastNotification]::new($ToastXml)

$Toast | Get-Member -MemberType Event

Register-ObjectEvent -InputObject $Toast -EventName Activated -Action {
    Out-File -FilePath C:\Temp\Event.txt -InputObject (Get-Date -Format 'o') -Append -Force
}

[Windows.UI.Notifications.ToastNotificationManager]::CreateToastNotifier($AppId).Show($Toast)