I have custom status “Backordered”. Iwan to change price in order with status backordered to 50.

here my code

    add_filter( 'woocommerce_order_status_backordered', 'change_backordered_to_processing', 100, 1 );
function change_backordered_to_processing( $order_id ){
    if( ! $order_id ) return;

    $order = wc_get_order( $order_id );

    if( $order->get_status() == 'backordered' ){
        $order->update_status( 'processing' );
        $order->set_status( 'processing' );

        foreach ($order->get_items() as $item_key => $item ){
             $item_id = $item->get_id();
             $new_product_price = 50
             $quantity     = (int)$item->get_quantity();

              // The new line item price
              $new_line_item_price = $new_product_price * $quantity;

             // Set the new price
              $item->set_subtotal( $new_line_item_price ); 
              $item->set_total( $new_line_item_price );
              $item->save(); // Save line item data



            }
        $order->calculate_totals();
        $order->save();
       }

return $order_id;

}

but it does not work. I change backordered to processing but cannot change price in order