Well, this question is old but still has no answer!
Here is a small solution for future visitors.
Implementing load more button for comments without plugins is simple enough:
- Create a button if comment pages are 2 and more
- Create a jQuery script that will process the button click event and passes the current comment page number to
wp_ajax_
action hook - The last step – is
wp_ajax_
function that will process the AJAX request.
That’s all!
But if you need the ready code, please look at this tutorial https://rudrastyh.com/wordpress/load-more-comments.html