Here is a really simple Configuration Manager Client installation PowerShell workflow. This workflow queries all the clients where ClientType property is NULL. You can easily add logging, scheduling etc.

workflow Install-CMClient
{
    Param(
        $SiteCode,
        $SiteServer
    )

    $Computers = Get-WmiObject -Namespace "Root\SMS\Site_$($SiteCode)" `
    -Query "Select Name from SMS_R_System where ClientType is NULL" -PSComputerName $SiteServer
    
    Write-Output -Input "Total computers without Configuration Manager Client:$($Computers.Count)"
    
    ForEach -parallel ($item in $Computers){

            $Path = "\\$($item.Name)\c$"

            if(Test-Path -Path $Path)
            {
               Write-Output -Input "Copying installation files to $($item.Name) TEMP folder"

               Copy-Item -Path  "\\Terminaator\CMClient" -Destination "\\$($item.Name)\c$\TEMP" -Recurse -Force
               
               Inlinescript{
                    Write-Output -Input "Starting CCMSETUP.EXE on $($Using:Item.Name)"
                    Start-Process -FilePath "C:\TEMP\CCMSETUP.EXE"
               } -PSComputerName $item.Name
            }
            Else{
                Write-Output -Input "----- Cannot access $Path -------------"
            }

    }
    
}
Install-CMClient -SiteCode TPT -SiteServer Localhost

This workflow generates following output.

image