add_backup_task.yml

---
- name: get {{ item.name }} backup information
  ansible.builtin.stat: path={{ item.dest }}/backup.marker
  register: backup_marker

- name: create {{ item.name }} backup
  ansible.builtin.command: mediavaultctl add --backup-name "{{ item.name }}" --source-folder "{{ item.source }}" --dest-folder "{{ item.dest }}"
  when: not backup_marker.stat.exists