mockup framework on how you could use SQLite database to track progress and store results for long running (days) scripts. This would allow for a script to be restarted from where it failed rather than having to start all the sites over.

Invoke-LongRunningTaskWithSqlLiteStorage.ps1

Import-Module -Name PSSQLite

function Initialize-Database
{
    [CmdletBinding()]
    param
    (
        [parameter(mandatory=$true)]
        [string]
        $Path,

        [parameter(mandatory=$true)]
        [System.Collections.Specialized.OrderedDictionary]
        $Schema,

        [parameter(mandatory=$false)]
        [switch]
        $Force
    )

    begin
    {
    }
    process
    {
        if( (Test-Path -Path $Path -PathType Leaf) -and -not $Force )
        {
            return
        }
        else
        {
            foreach( $s in $Schema.GetEnumerator() )
            {
                Write-Verbose "Executing Statement: $($s.value)"

                Invoke-SqliteQuery -Database $Path -Query $s.value
            }
        }
    }
    end
    {
    }
}

# connect to tenant

    # requires SharePoint > Application > Sites.FullControl.All
    Connect-PnPOnline -Url        "https://$env:CDX_TENANT-admin.sharepoint.com" `
                      -ClientId   $env:CDX_CLIENTID `
                      -Thumbprint $env:CDX_THUMBPRINT `
                      -Tenant     $env:CDX_TENANTID `
                      -ErrorAction Stop

# initialize database

    $path = "C:\_temp\sites.sqllite"

    $schema = [ordered] @{ 
    
        "INVENTORY" = "CREATE TABLE urls ( url VARCHAR(1000) PRIMARY KEY )" 
    
        "RESULTS"   = "CREATE TABLE results ( url VARCHAR(1000), filename VARCHAR(1000), contenttype VARCHAR(50), actorCount INT, actionCount INT )" 

    }

    Initialize-Database -Path "C:\_temp\sites.sqllite" -Schema $schema -ErrorAction Stop


# load database table

    if( ( Invoke-SqliteQuery -DataSource $path -Query "SELECT COUNT(*) FROM urls" -As SingleValue) -le 0 )
    {
        $drives = Get-PnPTenantSite -IncludeOneDriveSites -Filter "Url -like '.sharepoint.com/personal/'" -ErrorAction Stop

        $datatable = $drives | Select-Object Url | Out-DataTable -ErrorAction Stop

        Invoke-SQLiteBulkCopy -DataTable $datatable -DataSource $path -Table "urls" -Confirm:$false -ErrorAction Stop
    }

# process workload
    
    $urls = Invoke-SqliteQuery -DataSource $path -Query "SELECT url FROM urls" -As PSObject -ErrorAction Stop | Select-Object -ExpandProperty Url

    foreach( $url in $urls )
    {
        try
        {
            # do some work on site


            # update database w/ results of work

                $query = "INSERT INTO results ( url, fileName, contentType, actorCount, actionCount ) VALUES ( @url, @fileName, @contentType, @actorCount, @actionCount )"

                Invoke-SqliteQuery -DataSource $path -Query $query -SqlParameters @{ url = $url; filename = "foo.mp4"; contentType = "Recording"; actorCount = 1; actionCount = 1 } -ErrorAction Stop

            # remove site from inventory so it's not processed again

                Invoke-SqliteQuery -DataSource $path -Query "DELETE FROM urls WHERE url = @url" -SqlParameters @{ url = $url }

        }
        catch
        {
            # tbd - mark site as failed in database for reporting purposes?

            Write-Error "Site failed: $url. Error: $_"
        }
    }

# export results from sql to csv

    $results = Invoke-SqliteQuery -DataSource $path -Query "SELECT * FROM results" -As PSObject

    $results | Export-Csv -Path "C:\_temp\results.csv" -NoTypeInformation