@mcen1 ansible.posix is part of the Ansible community distribution, ansible · PyPI. But there are multiple things called “Ansible”, so they might only use ansible-core directly, which does not come with ansible.posix.
To elaborate on @felixfontein’s info: I am using RHEL9 repos (only thing we have offline access to) and I was able to install ansible-core from there but no posix stuff.