I created a new discussion with the same name since i could not reply on th eearlier one.

I want to confirm that I tested a non-interactive method which is working. Whoohoo.

Create a Scheduled Task which run e.g. at saturdays and run the command dcu-cli.exe with the parameters /applyupdates -silent. The Scheduled Task does run by the local SYSTEM account.
Below my configured scheduled task:

$taskname = "Dell Command Update"
$taskdescription = "Start of Dell Command Update process"
$action = New-ScheduledTaskAction -Execute "%ProgramFiles(x86)%\Dell\CommandUpdate\dcu-cli.exe" -Argument '/applyUpdates -silent'
$trigger = New-ScheduledTaskTrigger -Weekly -DaysOfWeek Saturday -At 05:00 -RandomDelay (New-TimeSpan -Hours 1)
$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Hours 2)
Register-ScheduledTask -Action $action -Trigger $trigger -TaskName $taskname -Settings $settings -Description $taskdescription -User "System" -RunLevel Highest

 

Above command does start and performs the scan in the background and applies the updates. Also a required restart is applied immediately as well.

I will continue testing with this, since this is what we require.