The hook part isn’t part of your original code:
add_shortcode( 'some_content', 'insert_before_comments' );
function insert_before_comments() {
ob_start(); ?>
<ul class="post-meta">
<li>Distance: <?php echo get_post_meta($post->ID, 'Distance', true); ?></li>
<li>Time: <?php echo get_post_meta($post->ID, 'Time', true); ?></li>
<li style="font-weight:500;"><?php echo get_post_meta($post->ID, 'Download', true); ?></li>
</ul>
<?php
return ob_get_clean();
}
Then your shortcode should be [some_content]
. If this doesn’t work then unfortunately we might be out of ideas.