WordPress shortcode for getting a list of categories (and the children, non-zero) for the given main category and print it out in a button list (for elementor)

wordpress_list_categories_and_children_shortcode.php

<?php

function list_categories_and_children($atributes)
{
    $atts = shortcode_atts(array(
        'main' => null
    ), $atributes);

    $cat_id = $atts['main'];
    if (isset($atts['main'])) {
    } else {
        $cat = get_category(get_query_var('cat'));
        $cat_id = $cat->cat_ID;
    }
    $child_categories = get_categories(
        array(
            'parent' => 30,
            'hide_empty'   => 0,
        )
    );

    $category = get_queried_object();
    $childCurrentClass = '';
    $single_use_case_wrapper = '';

    echo "<div class='category_filter_bar'><h5>Filter by:</h5>";
    echo "<ul>";

    if ($cat_id === 30) {
        $single_use_case_wrapper = 'current_category ';
    }
    echo "<li class='generic_button_list_wrapper'><a class='" . $single_use_case_wrapper . "elementor-button elementor-size-lg' href='" . esc_url(get_category_link(30)) . "'>All</a></li>";
    foreach ($child_categories as $child) {
        if (isset($cat->cat_name)) {
            if ($cat->cat_name === $child->cat_name) {
                $childCurrentClass = 'current_category ';
            } else {
                $childCurrentClass = '';
            }
        }
        echo "<li class='generic_button_list_wrapper'><a class='" . $childCurrentClass . "elementor-button elementor-size-lg' href='" . esc_url(get_category_link($child->term_id)) . "'>" . $child->cat_name . "</a></li>";
    }
    echo "</ul></div>";
    return null;
}

add_shortcode('listcategories', 'list_categories_and_children');