The fundamental problem is as described by the error:
selinux-policy-base >= 3.14.3-80.el8_5.2
Since none of your repos can provide this dependency, the installation cannot continue.
It seems that similar issues have happened before, and in that case the RHEL repos were simply lagging behind. You can try
sudo dnf upgrade --refresh again and see if the package is now available. If not, I don't think there's a good solution to this issue without including third party repositories (which is likely not a good idea).
As you can see here: https://pkgs.org/download/selinux-policy-base
...version 3.14.3-80 is currently available both on AlmaLinux and Rocky Linux, which are binary compatible with RHEL. It seems strange that RHEL would not have the package considering they are upstream to both of them.
Perhaps you are using a satellite repo that is out of date with upstream? You should investigate your repos as the source of this error I think.