WordPress - Random Slug

functions.php

<?php
add_filter('wp_unique_post_slug', 'seed_unique_slug', 10, 4);
function seed_unique_slug($slug, $post_id, $post_status, $post_type)
{
    if (in_array($post_type, ['post', 'product'])) {
        $post = get_post($post_id);
        if (empty($post->post_name) || $slug != $post->post_name) {
            $slug  = randomSlug();
        }
    }
    return $slug;
}

function randomSlug()
{
    $length = 5;
    $chars = 'abcdefghijklmnopqrstuvwxyz0123456789';
    $slug = '';
    for ($i = 0; $i < $length; $i++) {
        $slug .= substr($chars, wp_rand(0, strlen($chars) - 1), 1);
    }
    return $slug;
}