here is the quick discussion about SharePoint Workflow and Power Automate with Shakir Majeed Khan and Jerry Yasir

The script below will provide you list of sites in Site collection using SharePoint PNP PowerShell

$Creds = Get-Credential
$SiteUrl = "https://tenant.sharepoint.com/sites/sitecollection"
Connect-PnPOnline -Url $SiteUrl -Credentials $Creds
$Site = Get-PnPSite
$Web = Get-PnPWeb

function GetSubWebs($Web, $Context)
{
    $Global:SiteCount++
    $Context.Load($sweb.Webs)
    $Context.ExecuteQuery()
    foreach($aWeb in $sweb.Webs)
    {
        $aWeb.Url
        if($aWeb.Webs.Count > 0)
        {
            GetSubWebs $aWeb $Context
        }
    }
}

$Context= Get-PnPContext
$webs= $Web.Webs
foreach($sweb in $webs)
{
    $Context.Load($sweb)
    $Context.ExecuteQuery()
    $sweb.Url
    GetSubWebs $sweb $Context
}