Why does pagination work when hiding pinned posts in a loop?

Question

JavaScript

9 posts are given
, 4 of them are attached and are displayed by a separate request
, the rest of the posts should be displayed as usual with pagination of 6 pieces.

The loop displays 5 posts and a link appears to the second page, which shows an empty feed.
how to fix it?
logically, there is 1 more place for a post, and in general, pagination should not take into account attached articles when paginating,

the cycle code is as follows:

$sticky = get_option( 'sticky_posts' );
$paged  = get_query_var( 'paged' ) ?: 1;

$query  = new WP_Query( array(
  'ignore_sticky_posts' => 1,
  'post__not_in'        => $sticky,
  'posts_per_page'      => 6,
  'post_type' 		  => 'post',
  'paged'               => $paged
) );

  while( $query->have_posts() ){ $query->the_post();
    
    include ('parts/content-loop.php');
  }

upd: it was empirically found that post__not_in confuses pagination - no matter what gets there (just articles or sticks) - they are excluded from the request, and there is

nothing to do with pagination - it's not clear

yet upd2: it turned out that this is a known problem pagination when trying to exclude attached articles from the main loop or apply offset
Treated through the pre_get_posts function

For my task, it turned out to be easier to attach an arbitrary field to the post and use it to attach posts and multiple sorting

Answer 1

Final UPD (if I understood everything correctly):

const results = year.map(inner =>
  years.reduce((a, c) => a.concat(c.filter((v, i) => v == inner[i]).length > 1 ? [c] : []), []));

For each array in year, matches are displayed in a separate array.