WordPress: Related posts with WP_Query. https://since1979.dev/wordpress-related-posts-with-wp_query/

related-posts-loop-init.php

<?php if ($related_query->have_posts()) { ?>

    <div class="related-posts-grid">

        <?php while ($related_query->have_posts()) { ?>

            <?php $related_query->the_post(); ?>

            // ...

        <?php } ?>

    </div>

    <?php wp_reset_postdata(); ?>

<?php } ?>