Insert ads into archive?

Currently, we're using a plugin to insert an ad after every x posts in an archive, but I'm wondering if I could bypass the plugin and just do this through GeneratePress Elements?
Some generic code would be something like:

<?php while (have_posts()) : the_post(); $the_post_ids = get_the_ID(); $i ++?>
<?php if ($i == 5) : ?>
     <div class="ad">
	ad
     </div>
<?php endif; ?>

Is this possible? The plugin we're using is quite heavy for what we're using it for, just looking to streamline