Windows 11 assigned access - setting kiosk mode over powershell and WMI

Also tried it with powershell 7 and with another version of the script (also from an elevated cmd started with psexec)

$nameSpaceName = "root\cimv2\mdm\dmmap"
$className = "MDM_AssignedAccess"

# Schreiben Sie die XML-Konfiguration in eine Datei
$xmlContent = @"
<?xml version="1.0" encoding="utf-8"?>
<AssignedAccessConfiguration xmlns="http://schemas.microsoft.com/AssignedAccess/2017/config" xmlns:win11="http://schemas.microsoft.com/AssignedAccess/2022/config">
    <!-- ... Ihre XML-Konfiguration hier ... -->
</AssignedAccessConfiguration>
"@
$xmlFilePath = "win11-kiosk-wmi.xml"
$xmlContent | Set-Content -Path $xmlFilePath -Encoding UTF8

# Get-CimInstance, um die Instanz zu erhalten
$obj = Get-CimInstance -Namespace $nameSpaceName -ClassName $className

# Setzen Sie die Konfigurationseigenschaft des $obj-Objekts
$obj.Configuration = $xmlFilePath

# Aktualisieren Sie die Instanz mit der neuen Konfiguration
Set-CimInstance -CimInstance $obj

but also getting an error