Magento 2 get category collection with product count

CategoryHelper.php

<?php
namespace Namespacename\Modulename\Helper;

use Magento\Catalog\Model\Indexer\Category\Product\TableMaintainer;
use Magento\Framework\App\ObjectManager;
use Magento\Framework\App\Helper\AbstractHelper;
class CategoryHelper extends AbstractHelper
{
    /**
     * @var \Magento\Catalog\Model\ResourceModel\Category\CollectionFactory
     */
    private $categoryCollectionFactory;
    /**
     * @var TableMaintainer
     */
    private $tableMaintainer;
    /**
     * Store manager
     *
     * @var \Magento\Store\Model\StoreManagerInterface
     */
    protected $_storeManager;

    /**
     * CategoryHelper constructor.
     * @param \Magento\Framework\App\Helper\Context $context
     * @param \Magento\Catalog\Model\ResourceModel\Category\CollectionFactory $categoryCollectionFactory
     * @param \Magento\Store\Model\StoreManagerInterface $storeManager
     * @param TableMaintainer|null $tableMaintainer
     */
    public function __construct(
        \Magento\Framework\App\Helper\Context $context,
        \Magento\Catalog\Model\ResourceModel\Category\CollectionFactory $categoryCollectionFactory,
        \Magento\Store\Model\StoreManagerInterface $storeManager,
        TableMaintainer $tableMaintainer = null
    )
    {
        parent::__construct($context);
        $this->categoryCollectionFactory = $categoryCollectionFactory;
        $this->_storeManager = $storeManager;
        $this->tableMaintainer = $tableMaintainer ?: ObjectManager::getInstance()->get(TableMaintainer::class);

    }

    public function getStoreId()
    {
        return $this->_storeManager->getStore()->getId();
    }

    public function getCategoryCollectionWithProductCount()
    {
        $categoryCollection = $this->categoryCollectionFactory->create();
        $select = $categoryCollection->getSelect();
        $select->joinLeft(
                ['cat_index' => $this->tableMaintainer->getMainTable($this->getStoreId())],
                'cat_index.category_id=e.entity_id',
                ['product_count' => 'COUNT(DISTINCT cat_index.product_id)']
            )->group('e.entity_id');
        return $categoryCollection;
    }
}