Installing ansible-core and then the community.general collection using the ansible-galaxy works as expected with and without the rhel-system-roles RPM installed.

But after installing the ansible-freeipa RPM, "ansible-galaxy collection install community.general" shows this warning:

[WARNING]: Collection at '/usr/share/ansible/collections/ansible_collections/redhat/rhel_idm' does not have a MANIFEST.json file, nor has it galaxy.yml: cannot detect version.

It looks like the metadata for ansible-freeipa is incomplete or is different from rhel-system-roles which causes this warning. This also prevents installing redhat.rhel_idm from RH Automation Hub although that might be somewhat rare use case to install the same collection from two different sources.