On the final setup of using the cockpit ovirt wizard to install the hosted engine with 4.5.1, this occurs:

[ INFO ] TASK [ovirt.ovirt.hosted_engine_setup : Obtain SSO token using username/password credentials]
[ ERROR ] fatal: [localhost]: FAILED! => {"msg": "The field 'environment' has an invalid value, which includes an undefined variable. The error was: 'he_admin_username' is undefined\n\nThe error appears to be in '/usr/share/ansible/collections/ansible_collections/ovirt/ovirt/roles/hosted_engine_setup/tasks/auth_sso.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: Obtain SSO token using username/password credentials\n ^ here\n"}