SharePoint Online: Copy Folder Structure between Document Libraries using PowerShell

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

#Function to Copy All Folders from Source to Destination
Function Copy-SPOFolder
{
  param
    (
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $SourceFolder,
        [Parameter(Mandatory=$true)] [Microsoft.SharePoint.Client.Folder] $TargetFolder
    )
    Try {
        $Ctx = $TargetFolder.Context
        #Get all Folders from the Source
        $SubFolders = $SourceFolder.Folders
        $Ctx.Load($SubFolders)
        $Ctx.ExecuteQuery()
        Foreach($SubFolder in $SubFolders)
        {
            If($SubFolder.Name -ne "Forms")
            {
                #Prepare Target Folder
                $TargetFolderURL = $SubFolder.ServerRelativeUrl -replace $SourceLibrary.RootFolder.ServerRelativeUrl, $TargetLibrary.RootFolder.ServerRelativeUrl
                Try {
                        $Folder=$Ctx.web.GetFolderByServerRelativeUrl($TargetFolderURL)
                        $Ctx.load($Folder)
                        $Ctx.ExecuteQuery()
                        Write-host "Folder Already Exists:"$TargetFolderURL -f Yellow
                    }
                catch {
                        #Create Folder
                        if(!$Folder.Exists)
                        {
                            $Folder=$Ctx.Web.Folders.Add($TargetFolderURL)
                            $Ctx.Load($Folder)
                            $Ctx.ExecuteQuery()
                            Write-host "Folder Copied:"$TargetFolderURL -f Green
                        }
                    }
                #Call the function recursively
                Copy-SPOFolder -SourceFolder $SubFolder -TargetFolder $Folder
            }
        }
    }
    Catch {
        write-host -f Red "Error:" $_.Exception.Message
    }
}

#Function to Copy Folder Structure between document libraries
Function Copy-SPOFolderStructure
{
  param
    (
        [Parameter(Mandatory=$true)] [string] $SiteURL,
        [Parameter(Mandatory=$true)] [string] $SourceLibraryName,
        [Parameter(Mandatory=$true)] [string] $TargetLibraryName
    )
    Try {
        #Setup Credentials to connect
        $Cred= Get-Credential
 
        #Setup the context
        $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
        $Ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)
      
        #Get the source library and Target Libraries
        $SourceLibrary = $Ctx.Web.Lists.GetByTitle($SourceLibraryName)
        $Ctx.Load($SourceLibrary)
        $Ctx.Load($SourceLibrary.RootFolder)
        $TargetLibrary = $Ctx.Web.Lists.GetByTitle($TargetLibraryName)
        $Ctx.Load($TargetLibrary)
        $Ctx.Load($TargetLibrary.RootFolder)
        $Ctx.ExecuteQuery()

        #Call the function to copy folders from source library to the target
        Copy-SPOFolder -SourceFolder $SourceLibrary.RootFolder -TargetFolder $TargetLibrary.RootFolder
        }
    Catch {
        write-host -f Red "Error Copying File!" $_.Exception.Message
    }
}

#Set Parameter values
$SiteURL="https://crescent.sharepoint.com/sites/marketing"
$SourceLibraryName="Team Documents"
$TargetLibraryName="Project Documents"
 
#Call the function 
Copy-SPOFolderStructure -SiteURL $SiteURL -SourceLibraryName $SourceLibraryName -TargetLibraryName $TargetLibraryName