Adapted the functions written by Nick Wesselman to work directly in SPE.

SmartPublishItems.ps1

<#
    .NOTES
        Copied from Nick Wesselman's video https://www.youtube.com/watch?v=tXTbMRVF0ts
#>

function Start-Publish {
    param(
        [string]$Source = "master",
        [string]$Target = "web"
    )
    
    $sourceDb = [Sitecore.Data.Database]::GetDatabase($Source)
    $targetDb = [Sitecore.Data.Database]::GetDatabase($Target)
    $languages = [Sitecore.Globalization.Language]::GetLanguages($sourceDb)
    
    $handle = [Sitecore.Publishing.PublishManager]::PublishSmart($sourceDb, @($targetDb), $languages)
    $handle.ToString()
}

function Check-PublishStatus {
    param(
        [string]$HandleName
    )
    
    $handle = [Sitecore.Handle]::Parse($HandleName)
    [Sitecore.Publishing.PublishManager]::GetStatus($handle)
}

$handle = Start-Publish
$status = Check-PublishStatus -HandleName $handle
$processed = -1
while(-not $status.IsDone) {
    if($status.Processed -ne $processed) {
        $processed = $status.Processed
        Write-Host "Publishing: $($processed) items"
    }
    Start-Sleep -Seconds 1
    $status = Check-PublishStatus -HandleName $handle
}
Write-Host "Publishing: done"