How to add total count of posts in sub category to nested sidebar sub category?

Hello,
I would like to add “count” of posts under sub categories (in parenthesis) to a nested sidebar menu like;
-Category
– Sub Category A (5)
– Sub Category B (3)

I had found a code by your moderator (“DUDE”) to modify nested sidebar menu and added into my functions.php ;
(I’m not sure if it’s necessary)

add_filter('avf_sidebar_menu_filter', 'avia_add_parent_page_to_sidebar', 10, 3);
function avia_add_parent_page_to_sidebar($sidebar_menu, $args, $post)
{
    $parent = $post->ID;

    if(!empty($post->post_parent))
    {
        if(isset($post->ancestors)) $ancestors  = $post->ancestors;
        if(!isset($ancestors)) $ancestors  = get_post_ancestors($post->ID);
        $root		= count($ancestors)-1;
        $parent 	= $ancestors[$root];
    }

    $current = ($post->ID == $parent) ? "current_page_item" : "";

    $parent_page = '<li class="page_item page-item-'.$parent.' ancestor_page_item '.$current.'">';
    $parent_page .= '<a href="'.get_permalink($parent).'">'.get_the_title($parent).'</a>';
    $parent_page .= '</li>';

    $sidebar_menu = str_replace("<ul class='nested_nav'>", "<ul class='nested_nav'>{$parent_page}", $sidebar_menu);

    return $sidebar_menu;
}

Thank you