wc_get_products_by_tags.php

<?php
  // TODO: ecplain what does this code
  $tags = wp_get_post_terms($product_id, 'product_tag');
  $tag_slug = [];
?>
<?php if ($tags) :
  foreach ($tags as $tag) {
    $tag_slug[] = $tag->slug;
  }
  $args = [
    'post__not_in' => [$product_id],
    'post_type' => 'product',
    'product_tag' => $tag_slug
  ];
  $related_products = new WP_Query($args);
  ?>

  <div class="col-12">
    <div class="rounded_panel mt70">
      <h2>Related resources</h2>
      <div class="row">
        <div class="col-12 ">
          <ul class="relatedlinks">
            <?php if ($related_products) : ?>
              <?php while ($related_products->have_posts()): ?>
                <?php $related_products->the_post(); ?>

                <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>

              <?php endwhile; ?>
              <?php wp_reset_postdata(); ?>
            <?php endif; ?>

          </ul>
        </div>
      </div>
    </div>
  </div>
<?php endif; ?>