I don't think that WMI is Supported natively in XPE... you need the Win10ADK to install.
I never tried to setup XPE for WMI but you can try to install missing packages in your build and test if it works.
https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/winpe-add-packages--optional-components-reference (https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/winpe-add-packages--optional-components-reference)
Install the following packages
WinPE-Scripting
WinPE-WMI
WinPE-StorageWMI
WinPE-XML
WinPE-MDAC
WinPE-HTA
cmd example on a mounted image.
dism /image:C:\winpe_x86\mount /Add-Package /PackagePath:"C:\Program Files\Windows AIK\Tools\PETools\x86\WinPE_FPs\winpe-scripting.cab"
This is just a QS it might be more complicated.. than just that...