Magento 2.4.1 Custom sort option best sellers is not working

Question

I have created a custom bestsellers sorting option, the query working fine but setOrder() and order() is not working, i want to sorting the values using qty_ordered

<?php

namespace Vendor\Module\Block\Product\ProductList;

class Toolbar extends \Magento\Catalog\Block\Product\ProductList\Toolbar
{
    public function setCollection($collection)
    {  
         $this->_collection = $collection;
       
        if($this->getCurrentOrder() == "bestseller")
        {
           $this->_collection->getSelect()->joinLeft(
                'sales_order_item',
                'e.entity_id = sales_order_item.product_id',
                array('qty_ordered' => 'SUM(sales_order_item.qty_ordered)'))
                ->group('e.entity_id')
                 ->order('qty_ordered ' . $this->getCurrentDirectionReverse());
              
        }

           


        // $this->_collection->setCurPage($this->getCurrentPage());

        // $limit = (int)$this->getLimit();
        // if($limit)
        // {
        //     $this->_collection->setPageSize($limit);
        // }
        // if($this->getCurrentOrder())
        // {
        //     $this->_collection->setOrder($this->getCurrentOrder(), $this->getCurrentDirection());
        // }
        
        return $this->_collection;
    }

    public function getCurrentDirectionReverse()
    {
        if($this->getCurrentDirection() == 'asc')
        {
            return 'desc';
        }
        elseif($this->getCurrentDirection() == 'desc')
        {
            return 'asc';
        }
        else
        {
            return $this->getCurrentDirection();
        }
    }

}

order() asc or desc is not working