Post Page Not Showing Featured Image

I too have the same problem. I don’t think this theme shows a featured image on the single page. It would be good if it did.
I managed to bodge it by adding this to (my child theme’s) single.php

<?php
if ( has_post_thumbnail() ) { // check if the post has a Post Thumbnail assigned to it.
the_post_thumbnail( 'full' );
}
?>

(Insert after <?php while ( have_posts() ) : the_post(); ?>)

Or this https://www.wpbeginner.com/beginners-guide/how-to-add-featured-image-or-post-thumbnails-in-wordpress/