category header without category template

I wanted to have a category header using a post (for ease of adding, updating, …) So that for a new header post I should select the category ‘header’ AND the category it describe.

So I went with this code:
in theme-child/functions.php :

add_action( 'pre_get_posts', 'exclude_category' );
function exclude_category($query){
  global $wp_the_query;
  if (!$query->is_admin && $wp_the_query == $query ) {
    $query->set( 'cat', -68 );
  }
  return $query;
};

here the ‘header’ category (68) is excluded from every pages except admin pages

and in category.php I added before calling the loop

if (paged < 2) :
	 $apropos_query = new WP_Query($query_string . '&cat=68');
	 while ( $apropos_query->have_posts() ):
                $apropos_query->the_post();
	 	the_title();
	 endwhile;
 endif;

here the new query to show the category header post

Was this a proper way to do it, is there a better/simpler way ?