Need advice/support with a PowerShell script

$key = (1..16)  
$plainPassword = 'password' 
$secureString = ConvertTo-SecureString -String $plainPassword -AsPlainText -Force
$encryptedPassword = ConvertFrom-SecureString -SecureString $secureString -Key $key
$encryptedPassword | Out-File "C:\path\encryptedpassword.txt"

<Configuration>
  <UserName>USER</UserName>
  <Password>ENCRYPTED
</Password>
</Configuration>

Add-Type -Path "C:\Program Files (x86)\WinSCP\WinSCPnet.dll"
[xml]$config = Get-Content "C:\path\config.xml"
$securePassword = ConvertTo-SecureString $config.Configuration.Password
$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Sftp
    HostName = "FQDN"
    PortNumber = PORT
    UserName = $config.Configuration.UserName
    SecurePassword = $securePassword
    GiveUpSecurityAndAcceptAnySshHostKey = $true 
}
$session = New-Object WinSCP.Session
try {
    $session.Open($sessionOptions)
 
    # Define paths
    $localPath = "C:\Users\test\Downloads\test\*"
    $remotePath = "/share/remotetest/"
 
    # Synchronize files
    $synchronizationResult = $session.SynchronizeDirectories([WinSCP.SynchronizationMode]::Local, $localPath, $remotePath, $true)
 
    # Throw on any error
    $synchronizationResult.Check()
}
finally {
    $session.Dispose()
}
 
Write-Host "Synchronization complete."

ConvertTo-SecureString : The parameter value "NOT THE ACTUAL ENCRYPTED STRING
" is not a valid encrypted string.
At line:8 char:19
+ ... ecurePassword = ConvertTo-SecureString $config.Configuration.Password
+                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [ConvertTo-SecureString], PSArgumentException
    + FullyQualifiedErrorId : ImportSecureString_InvalidArgument,Microsoft.PowerShell.Commands.ConvertToSecureStringCommand
 
New-Object : The value supplied is not valid, or the property is read-only. Change the value, and then try again.
At line:11 char:19
+ $sessionOptions = New-Object WinSCP.SessionOptions -Property @{
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidData: (:) [New-Object], Exception
    + FullyQualifiedErrorId : SetValueException,Microsoft.PowerShell.Commands.NewObjectCommand
 
Exception calling "Open" with "1" argument(s): "Value cannot be null.
Parameter name: sessionOptions"
At line:23 char:5
+     $session.Open($sessionOptions)
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ArgumentNullException
 
Synchronization complete.

$securePassword = ConvertTo-SecureString $config.Configuration.Password -Key $key

$username = "testtest"
$password = "testtest"
cmdkey /generic:fqdn.com /user:$username /pass:$password

# Define the local and remote paths
$localPath = "C:\testfolder\"
$remotePath = "/testfolder/test"
 
# Define the SFTP server details
$ftpServer = "fqdn.com"
$port = 2222
 
# Function to get credentials from Windows Credential Manager
function Get-CredentialFromManager {
    param (
        [string]$target
    )
 
    $cred = cmdkey /list:$target 2>&1 | Select-String -Pattern "User:"
    if ($cred) {
        $username = $cred -replace ".*User: (.*)", '$1'
        $password = ConvertFrom-SecureString -SecureString (New-Object System.Management.Automation.PSCredential($username, (Read-Host -AsSecureString "Enter password for $username")).Password) -AsPlainText
        return New-Object -TypeName PSCredential -ArgumentList $username, (ConvertTo-SecureString $password -AsPlainText -Force)
    } else {
        throw "Credentials not found in Windows Credential Manager for $target"
    }
}
 
# Load the credentials from the Windows Credential Manager
try {
    $credential = Get-CredentialFromManager -target $ftpServer
    $username = $credential.UserName
    $password = $credential.GetNetworkCredential().Password
} catch {
    Write-Error $_.Exception.Message
    exit 1
}
 
# Secure the password
$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
 
# Define the WinSCP assembly location
$WinSCPPath = "C:\Program Files (x86)\WinSCP\WinSCPnet.dll"
 
# Load the WinSCP .NET assembly
Add-Type -Path $WinSCPPath
 
# Create a new WinSCP session
$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Sftp
    HostName = $ftpServer
    PortNumber = $port
    UserName = $username
    Password = $securePassword
    SshHostKeyFingerprint = "ssh-ed25519 256 SHA256:xxx"
}
 
$session = New-Object WinSCP.Session
 
try {
    # Connect to the server
    $session.Open($sessionOptions)
 
    # Synchronize the files
    $synchronizationResult = $session.SynchronizeDirectories(
        [WinSCP.SynchronizationMode]::Remote,
        $localPath,
        $remotePath,
        $False,
        [WinSCP.SynchronizationCriteria]::Checksum
    )
 
    # Check for errors
    if ($synchronizationResult.IsSuccess) {
        Write-Host "Synchronization succeeded!"
    } else {
        Write-Host "Synchronization failed with errors:"
        $synchronizationResult.Failures | ForEach-Object { Write-Host $_.Message }
    }
} finally {
    # Disconnect from the server
    $session.Dispose()
}

 : Credentials not found in Windows Credential Manager for fqdn.com
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException

# Importieren des CredentialManager-Moduls
Import-Module CredentialManager
 
# Definieren Sie die Zieladresse der Anmeldeinformationen
$server = "server.server.com"
$port = 2222
$credentialTarget = "${server}:${port}"
 
$credential = Get-StoredCredential -Target $credentialTarget
 
if ($credential -eq $null) {
    Write-Host "Anmeldeinformationen für $credentialTarget wurden nicht gefunden."
    exit 1
} else {
    Write-Host "Anmeldeinformationen erfolgreich abgerufen."
}
function ConvertFrom-SecureStringToPlainText {
    param (
        [System.Security.SecureString]$secureString
    )
    $ptr = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($secureString)
    try {
        return [System.Runtime.InteropServices.Marshal]::PtrToStringBSTR($ptr)
    }
    finally {
        [System.Runtime.InteropServices.Marshal]::ZeroFreeBSTR($ptr)
    }
}
Add-Type -Path "C:\Program Files (x86)\WinSCP\WinSCPnet.dll"
 
try {
    $passwordPlainText = ConvertFrom-SecureStringToPlainText -secureString $credential.Password
    $sessionOptions = New-Object WinSCP.SessionOptions
    $sessionOptions.Protocol = [WinSCP.Protocol]::Sftp
    $sessionOptions.HostName = $server
    $sessionOptions.PortNumber = $port
    $sessionOptions.UserName = $credential.UserName
    $sessionOptions.Password = $passwordPlainText
    $sessionOptions.SshHostKeyFingerprint = "ssh-rsa SHA256:xxx"
    Write-Host "Sitzungseinstellungen erfolgreich konfiguriert."
}
catch {
    Write-Host "Fehler beim Konfigurieren der Sitzungseinstellungen: $($_.Exception.Message)"
    exit 1
}
 
$session = New-Object WinSCP.Session
 
try {
    # Sitzung öffnen
    $session.Open($sessionOptions)
    Write-Host "Erfolgreich mit dem SFTP-Server verbunden."
}
catch {
    Write-Host "Verbindung zum SFTP-Server fehlgeschlagen: $($_.Exception.Message)"
}
finally {
    # Sitzung schließen, falls geöffnet
    if ($session.Opened) {
        $session.Dispose()
    }
}