P7Zip is required to extract certain archive files, especially the .7z kind. It isn't available in the RHEL 8 repositories, so you're going to need to get it elsewhere. For that, there are two options, the EPEL and building it from source. Both work well.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-install-p7zip-on-redhat-8