OSPd minor update asks to "Log into the cephadm shel" from a controller node, then follow Ceph upgrade guide which is mostly about upgrading from one major Ceph version to the following, and starts asking you to run subscription-manager and dnf, which can't be run inside cephadm:

https://docs.redhat.com/en/documentation/red_hat_openstack_platform/17.1/html/deploying_an_overcloud_in_a_red_hat_openshift_container_platform_cluster_with_director_operator/assembly_performing-a-minor-update-of-the-rhosp-overcloud-with-director-operator#proc_updating-the-red-hat-ceph-storage-cluster_preparing-OSPdO-for-a-minor-update

Minor update should be probably similar to the regular director deployment upgrade steps described here:

https://docs.redhat.com/en/documentation/red_hat_openstack_platform/17.1/html/performing_a_minor_update_of_red_hat_openstack_platform/assembly_updating-the-overcloud_keeping-updated#proc_updating-the-ceph-storage-cluster_updating-overcloud