user editable post type description

I am trying to make the post type description user editable. While I am able to access the settings-page data via rwmb_meta('_prefix_classic_editor', ['object_type' => 'setting'], 'posttype_description') inside a template like archive.php, I can't inside my register post types function like so:

function prefix_register_post_types()
{
    $cpt_labels = [...];

    register_post_type('cpt', [
        'label' => esc_html__('cpts', '_textdomain'),
        'labels' => $cpt_labels,
        'description' => rwmb_meta('prefix_classic_editor', ['object_type' => 'setting'], 'posttype_description'),
        'public' => true,
        'hierarchical' => false,
        'exclude_from_search' => false,
        'publicly_queryable' => true,
        'show_ui' => true,
        'show_in_nav_menus' => true,
        'show_in_admin_bar' => true,
        'show_in_rest' => true,
        'query_var' => true,
        'can_export' => true,
        'delete_with_user' => true,
        'has_archive' => true,
        'rest_base' => '',
        'show_in_menu' => true,
        'menu_icon' => 'dashicons-awards',
        'menu_position' => 5,
        'capability_type' => 'post',
        'supports' => ['title', 'editor', 'thumbnail', 'excerpt'],
        'taxonomies' => [],
        'rewrite' => [
            'with_front' => false,
        ],
    ]);
}

add_action('init', 'prefix_register_post_types');

any idea on how to accomplish this?