您可以使用以下方法更新新价格-

$order_id = 123;

$order = wc_get_order( $order_id );

foreach( $order->get_items() as $item_id => $item ){
    $new_product_price = 30;
    $product_quantity = (int) $item->get_quantity();
    
    $new_line_item_price = $new_product_price * $product_quantity;
    
    $item->set_subtotal( $new_line_item_price ); 
    $item->set_total( $new_line_item_price );

    $item->save(); // Save line item data
}
$order->calculate_totals();