Automatic Virtual Machine Activation

As long as your Hyper-V underlying licensing is in place, this is a good approach to activate Microsoft virtual machines:

https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/dn303421%28v%3dws.11%29#avma-keys

A nice writeup on the topic here:

https://redmondmag.com/articles/2019/10/03/automating-vm-activation-in-hyperv.aspx