Copy of a large number of folders from one sharepoint online site to another

You can use the below script for copying. Attached the sample csv to be used. This script does not preserve metadata.

function Copy-sharepoint
{
Param(
[Parameter(Mandatory=$True)]
[String]$sharepointUrl,

[Parameter(Mandatory=$True)]
[String]$UserName,

[Parameter(Mandatory=$True)]
[String]$Password,

[Parameter(Mandatory=$True)]
[String]$Path,

[Parameter(Mandatory=$True)]
[System.Management.Automation.PSCredential]$cred

)
#create secure password
$sPassword = $Password | ConvertTo-SecureString -AsPlainText -Force

$loadInfo1 = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
$loadInfo2 = [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.Runtime")
$csvs = Import-Csv $Path

Foreach($csv in $csvs)
{

$Sourceurl = $csv.SourceUrl
$souceFoldername= $csv.Foldername
$targeturl = $csv.TargetUrl
$TargetDocumentLib = $csv.targetlib

Connect-PnPOnline -Url $Sourceurl -Credentials $cred
$Files= Find-PnPFile -Folder $souceFoldername -Match *
Disconnect-PnPOnline
$Loginsource =$false
$webClient = New-Object System.Net.WebClient 
$webClient.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($UserName, $sPassword)
$webClient.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f")
$webclient.Proxy = $null
Write-Host "Copying $($Files.count) files to $($targeturl)"

foreach($file in  $Files)
{
    $pageUrl = $sharepointUrl+$file.ServerRelativeUrl
    $UniqueFileName = $file.Name
    $ByteArray=$webClient.DownloadData($pageUrl)
    $tfolderWithname= ($pageUrl -split $Sourceurl)[1]
    $tfolderwiths =($tfolderWithname -split $UniqueFileName)[0]
    $tfolderrmstr =$tfolderwiths.TrimStart("/")
    $tfolder =$tfolderrmstr.TrimEnd("/")
    $fstream = [System.IO.MemoryStream]($ByteArray)
    
    $tf=($tfolder -split "/")
         $test=$False
         If($tf.count -gt 1)
         {
             foreach($tf1 in $tf)
             {
                 if($test -eq $true)
                 {
                    $tf2=$tf2+"/"+$tf1
                 }
                    $test=$true
              }
          }
          Else
          {
          $tf2=$null
          }
    
     If($Loginsource -eq $false )
        {
            Connect-PnPOnline -Url $targeturl -Credentials $cred         
            $Loginsource =$true
           
        }
    
    $m=Get-PnPList -Identity $TargetDocumentLib
    $ctx=Get-PnPContext
    $mroot=$m.RootFolder
    $ctx.Load($mroot)
    $ctx.ExecuteQuery()
    $targetFolder=$mroot.Name+$tf2
    $tf2=$null

    If($targetFolder -notlike "*Forms")
    {
        
            Add-PnPFile -FileName $UniqueFileName -Folder $targetFolder -Stream $fstream
        
    }
}

}
}

$cred=Get-Credential 
$Path = "C:\csv\copyfile.csv"
$sharepointUrl = "https://tenantname.sharepoint.com"
$UName=$cred.UserName.ToString()
$Pass =$cred.GetNetworkCredential().Password

Copy-sharepoint -UserName $UName -Password $Pass -cred $cred -sharepointUrl $sharepointUrl -Path $Path