The Ansible collection for Satellite does not support comparing content view versions.
Due to that, customers must fall back to direct API calls using ansible.builtin.uri:

  tasks:
    - name: Obtain differences
      ansible.builtin.uri:
        url: "{{ server_url }}/katello/api/packages/compare"
        user: "{{ username }}"
        password: "{{ password }}"
        method: GET
        body_format: json
        body:
          content_view_version_ids: ["\{{ cv_version_id_1 }}", "\{{ cv_version_id_2 }}"]
          restrict_comparison: "different"
        force_basic_auth: true
      register: differences

Customer is requesting the ability to perform this natively via the collection without having to resort to running API calls directly.