There is a bit of history behind it and other Red Hat Enterprise Linux clones. Originaly there was CentOS which was the "open source" / free version of RHEL. It was known for stability and reliability as a Linux distro for enterprise applications. CentOS was also 1-1, bug-for-bug replacement for RHEL.

This was good for a long time, but Red Hat dropped support for CentOS a few years back and stopped updating it. So Rocky Linux, Alma Linux, and others popped up to replace CentOS.