Hi! I have been exploring the same lately. I need to perform the same too (migration and changing domain name). Stumbled upon the same link as you. But again, I was not confident about the procedure shared in the link.
Later, I even stumbled upon a response by @yanokwa over this thread for the same:
I am still unsure if it is a good idea to follow the procedure mentioned on: https://dev.to/kagundajm/odk-central-domain-change-a-painless-backup-and-restore-tutorial-4gpk
I guess the procedure shared by @yanokwa is quite different than what is being told in that article?!