Infinite scroll in single post

Hi all,
Testing Infinite Scroll in a development environment. I am using a custom theme based on underscores.me starter theme. Infinite scroll is working fine in archive pages (both tag and category) but it doesn’t work on the single post page.
I have a section under the main loop with ‘Read Also’ and want to use there the inf loop.
This is the code from the single.php:

<section class="related-posts-container">
 <span class="read-also">
  <span>Read Also</span>
 </span>
 <div id="infinite" class="related-posts">
<?php
 $categories = get_the_category($post->ID);
 $catid = $categories[0]->cat_ID;
 $currpost[] = get_the_ID();
 $args = [
 'post_type' => 'post',
 'post_status' => 'publish',
 'orderby' => 'DESC',
 'cat' => $catid,
 'post__not_in' => $currpost,
  ];
 $query = new WP_Query( $args );
if ($query->have_posts()) : while ($query->have_posts()) : $query->the_post();
  get_template_part('template-parts/infinite');
endwhile;
endif;
?>
</div> <!--End Infinite Loop -->
</section> <!--End Related Posts Container-->

This is the altered code from jetpack.php:

add_theme_support( 'infinite-scroll', array(
   'container' 	    => 'infinite',
   'render'    	    => 'ths_infinite_scroll_render',
   'footer'    	    => false,
   'wrapper'	    => true,
   'posts_per_page' => 6,
) );

And the renderer function:

function ths_infinite_scroll_render() {
  while ( have_posts() ) {
     the_post();
	if ( is_search() ) :
	  get_template_part( 'template-parts/content', 'search' );
	else :
	  get_template_part( 'template-parts/infinite', get_post_format() );
	endif;
	}
}

Is it because it’s in locahost? Is there something i’m missing on Jetpack setup?
I’ve tried other infinite scroll plugins and they work (with a shortcode though). I’ve tried TwentyTwenty theme and have the same problem.
Please advice.