You can use PowerShell script for deleting SharePoint first stage Recycle Bin and second stage Recycle Bin items.
Based on SharePoint version you are using, you can refer PowerShell scripts given below:
For SharePoint online: SharePoint Online: Empty Recycle Bin using PowerShell
For SharePoint Server / On-Premises: Empty SharePoint Recycle Bins Programmatically with PowerShell
For SharePoint Online, you can use PnP PowerShell code like below:
$SiteURL = "https://Crescent.sharepoint.com"
$username = "[email protected]"
$password = "XXXXXXXXX"
$encpassword = convertto-securestring -String $password -AsPlainText -Force
$cred = new-object -typename System.Management.Automation.PSCredential -argumentlist $username, $encpassword
#Connect to SharePoint Online site
Connect-PnPOnline -Url $SiteURL -Credentials $cred
#Empty Recycle Bins: Both 1st stage and 2nd Stage
Clear-PnPRecycleBinItem -All -Force