Reading the guide:
https://wiki.almalinux.org/elevate/ELevating-CentOS7-to-AlmaLinux-9.html
Mentions about
sudo yum install -y leapp-upgrade leapp-data-almalinux
But that packages are not found in the repository or are not fetched, so it cannot be installed, in particular leapp-data-almalinux
I can find https://repo.almalinux.org/elevate/el7/x86_64/leapp-0.14.0-1.el7.noarch.rpm
Which is pretty outdated compared with SRPMs
https://repo.almalinux.org/elevate/el7/SRPMS/
Could you release new updated files in the repository?