FYI The person who created that video I believe followed this other person's website devoted to all the details of getting it to work:

https://www.nicksherlock.com/2020/04/installing-macos-catali...

one cool thing is - once you have it installed, you can clone it freely and even remote log into several at once.

I believe they even figured out how to run them on those 32-core or 64-core amd threadrippers.