Here is a sanitized version of my unattend.xml file and how I call the sysprep. I used pretty much the same unattend.xml file with windows 10 deployments.
https://forums.fogproject.org/topic/11920/windows-10-1803-sysprep-problem/7
I might recommend that you build your reference image on a virtual machine so you can take snapshots to save the system state as important steps. This saves countless hours of having to start over from the beginning when something goes bad.