Windows Restricted User Experience Set-CimInstance Error

So I'm trying to set up a restricted user experience that allows the usage of only one application. However, I keep running into this weird error message that provides no useful information:

I've been successful in getting the boilerplate example from the official Windows guide to work, so I'm fairly certain the error lies in how I've set up the Allowed Apps and PinnedList. Perhaps in the path to the app? But I'm not sure how I'd go about changing that since I got the pathway from the task manager. Any help is appreciated!

Full code below:

psexec.exe -i -s powershell.exe

$assignedAccessConfiguration = @"
<?xml version="1.0" encoding="utf-8"?>
<AssignedAccessConfiguration xmlns="http://schemas.microsoft.com/AssignedAccess/2017/config" xmlns:rs5="http://schemas.microsoft.com/AssignedAccess/201810/config" xmlns:v3="http://schemas.microsoft.com/AssignedAccess/2020/config" xmlns:v5="http://schemas.microsoft.com/AssignedAccess/2022/config">
  <Profiles>
    <Profile Id="{9A2A490F-10F6-4764-974A-43B19E722C24}">
      <AllAppsList>
        <AllowedApps>
          <App AppUserModelId="Microsoft.RemoteDesktop_10.2.3012.0_x64__8wekyb3d8bbwe" />
        </AllowedApps>
      </AllAppsList>
      <v5:StartPins><![CDATA[{
                    "pinnedList":[
                        {"packagedAppId":"Microsoft.RemoteDesktop_10.2.3012.0_x64__8wekyb3d8bbwe"},
                    ]
                }]]></v5:StartPins>
      <Taskbar ShowTaskbar="true" />
    </Profile>
  </Profiles>
  <Configs>
    <Config>
      <AutoLogonAccount rs5:DisplayName="RDUSER" />
      <DefaultProfile Id="{9A2A490F-10F6-4764-974A-43B19E722C24}" />
    </Config>
  </Configs>
</AssignedAccessConfiguration>
"@

$namespaceName="root\cimv2\mdm\dmmap"
$className="MDM_AssignedAccess"
$obj = Get-CimInstance -Namespace $namespaceName -ClassName $className
$obj.Configuration = [System.Net.WebUtility]::HtmlEncode($assignedAccessConfiguration)
Set-CimInstance -CimInstance $obj