Old order screen?

Old admin orders list was to heavy and has been removed since Woocommerce 3. So to get that back on, that needs a custom development, assuming that the displayed order list will be heavier again.

So you will need to hire a developer, if you don’t know how to do it.

This code should show an order items column.

add_filter( 'manage_shop_order_posts_columns', 'set_shop_order_posts_columns', 99 );
function set_shop_order_posts_columns( $columns ) {
  $columns['order_items'] = 'Order items';
  return $columns;
}

add_action( 'manage_shop_order_posts_custom_column' , 'show_custom_columns', 10, 2 );
function show_custom_columns( $column_name, $post_id ) {
  switch ( $column_name ) {
    case 'order_items':
      $order = new WC_Order( $post_id );
      $order_items = $order->get_items();
      $nr = 1;
      foreach( $order_items as $order_item ) {
        print $nr.') '.$order_item->get_name().'<br>';
        $nr++;
      }
      break;
  }
}

The code can be added to functions.php in your child theme or you can use the “My Custom Functions” plugin.