Add multiple custom post types in functions.php, but only one custom post type show in dashboard

add add_action('init', 'create_new_cpt2'); in your snippet and modify add_db_to_article function as below,

function add_db_to_article ($post_types) {
    $custom_post_types = array ('article', 'news');
    $output = array_merge($post_types, $custom_post_types);
    return $output;
}

Note: ‘news’ is added in $custom_post_types array.