We have WU blocked as all patching is handled by MEMCM. I found this workaround script to temporarily enable in the registry, add the feature, then set the registry back to what is was prior.
$currentWU = Get-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU" -Name "UseWUServer" | select -ExpandProperty UseWUServer
Set-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU" -Name "UseWUServer" -Value 0
Restart-Service wuauserv
Get-WindowsCapability -Name RSAT* -Online | Add-WindowsCapability –Online
Set-ItemProperty -Path "HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU" -Name "UseWUServer" -Value $currentWU
Restart-Service wuauserv