I am afraid that scripts will not work in our env because the CentOS installations have no access to repos in the internet.
Elevate/Leapp can be configured to retrieve *8 pkgs from your internal repository which in turn a mirror of internet ones.
I also dont want to do migrate to CentOS 8 and then to one of this new distros.
The Elevate/Leapp approach is from CentOS 7 to RL/OL/AL 8 directly.
Some cases need fresh rebuild of machines and in different cases in-place upgrade is viable option.