With MECM (SCCM) you can deploy a new Windows 10 build in two ways. You can deploy Windows 10 build as a feature update (Servicing) or you can create a task sequence (in-place-upgrade).

In my opinion with a task sequense you can easy create pre and post actions based on variables but the time that a user can’t use the computer (downtime) can be quiet long.

Deploying the feature update with servicing is much more user friendly, because there is almost no downtime for the user. Creating pre and post actions can be done but are not easy and can’t be based on variables like task sequence steps can.