permanently deletes a sharepoint site

the only way to do that is by using Powershell

#Permanently Delete a SharePoint Site Collection.
 Import-Module Microsoft.Online.SharePoint.PowerShell -DisableNameChecking 
$tenant ="https://tenantdomain-admin.sharepoint.com"
$site="https://tenantdomain.sharepoint.com/sites/testDre1"
#$credential = Get-credential
Connect-PnPOnline -url $tenant -Credential 'CIE'

#This command will delete the SharePoint site collection. You must replace the url "https://contoso.sharepoint.com/sites/SiteCollectionName" with your Sharepoint Online URL and use the Site Collection Name that is to be deleted for this script to work properly.

Remove-PnPTenantSite -url  $site

#This command will pause the script for 20 seconds before proceeding.
#Start-Sleep -s 20

#This script will permanently delete the SharePoint site collection after it is sent to the SharePoint Site Recycle Bin. You must replace the url “https://contoso.sharepoint.com/sites/SiteCollectionName” with your Sharepoint Online URL and use your Site Collection Name that is to be permanently deleted for this script to work properly.
Clear-PnPTenantRecycleBinItem -url  $site  -Wait