A few notes from my rather modest experiences with Rocky . . .
The two main repos for Rocky 8.4 are:
http://dl.rockylinux.org/pub/rocky/8.4/BaseOS/
http://dl.rockylinux.org/pub/rocky/8.4/Appstream
Rocky uses DNF
Rocky uses the Anaconda installer
I converted a Centos 8 system to Rocky very easily - see this thread Transition from CentOS to Rocky - #37 by Iainwhite