Among the many bad things that happened in 2021 was the official end of CentOS 8, which hit EOL at the end of the calendar year (but if you were running on CentOS 7, which is POWER9-compatible, you're golden until June 2024). CentOS Stream is a thing, though, and for those of you who want something a little less, uh, bubbly than Fedora but more current than RHEL, it's an option.
Still, the loss of CentOS's celebrated stability guarantee stings, and for some of you so will the price of an RHEL subscription, which is why at least two distros sprang up to be the next "CentOS classic": Rocky Linux and AlmaLinux. Currently, Rocky Linux doesn't list a Power ISA build on its main download page or alternative architectures page. On the other hand, AlmaLinux 8.5 is now available as a beta for ppc64le (read the release notes), and claims full 1:1 binary compatibility with RHEL 8.5 to purportedly allow an almost literal drop-in experience; a single command will swap repositories and keys from CentOS 8.x. AlmaLinux states it will be supported until at least 2029.