How to update cart after deleting line items?
instead of using $item->delete() this works:

  $cart_manager = \Drupal::service('commerce_cart.cart_manager');
  foreach($items as $item) {
    //$item-&gt;delete();
    $cart_manager-&gt;removeOrderItem($cart, $item, TRUE);
  }


the 3rd parameter is 'save cart' and setting it to TRUE updates the cart Total.