Results not being printed

You’re _doing_it_wrong, as $product is an object.

I’m pretty sure you want something like this:

$args = array(
    'post_type' => 'product',
    'posts_per_page' => 4,
);
$featured_query = new WP_Query($args);

if ($featured_query->have_posts()) {
    while ($featured_query->have_posts()) {
        $featured_query->the_post();
        ?>
        <h1 class="post-title"><?php the_title(); ?></h1>
        <div class="post-content"><?php the_content(); ?></div>
        <?php
    }
    wp_reset_postdata();
}