Do not duplicate posts with multiple categories in multiple loops

Question

If I post an article and define several categories, in this case all that are in the loops, the only post that will appear will be the one, because it is the last one.

What I want is that the last post of each category appears without repeating, if the last post is in several categories, then I want it to show the penultimate one.

With $do_not_duplicate[] = $post->ID; does not work

How the posts are appearing:

Code:

<?php $page = (get_query_var('page')) ? get_query_var('page') : 1;
        $args = array( 'post_type' => 'post', 'posts_per_page' => 1, 'page' => $page, 'cat' => 'cat=2 ' );
        $wp_query = new WP_Query($args);
        while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID;  ?>
                <div class="intro-noticia-1">
                    <a href="<?php the_permalink(); ?>">
                <?php $backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'large' );?>
                <div class="intro-post-thumbnail" style="background: url('<?php echo $backgroundImg[0]; ?>'); background-size: cover; background-position: center;">
                </div></a>
                </div>
        <?php endwhile; ?>

                <?php $page = (get_query_var('page')) ? get_query_var('page') : 1;
        $args = array( 'post_type' => 'post', 'posts_per_page' => 1, 'page' => $page, 'cat' => 'cat=3 ' );
        $wp_query = new WP_Query($args);
        while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID;  ?>
                <div class="intro-noticia-2">
                    <a href="<?php the_permalink(); ?>">
                <?php $backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'large' );?>
                <div class="intro-post-thumbnail" style="background: url('<?php echo $backgroundImg[0]; ?>'); background-size: cover; background-position: center;">
                </div></a>
                </div>
        <?php endwhile; ?>

                <?php $page = (get_query_var('page')) ? get_query_var('page') : 1;
        $args = array( 'post_type' => 'post', 'posts_per_page' => 1, 'page' => $page, 'cat' => 'cat=4 ' );
        $wp_query = new WP_Query($args);
        while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID;  ?>
                <div class="intro-noticia-3">
                    <a href="<?php the_permalink(); ?>">
                <?php $backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'large' );?>
                <div class="intro-post-thumbnail" style="background: url('<?php echo $backgroundImg[0]; ?>'); background-size: cover; background-position: center;">
                </div></a>
                </div>
        <?php endwhile; ?>

                <?php $page = (get_query_var('page')) ? get_query_var('page') : 1;
        $args = array( 'post_type' => 'post', 'posts_per_page' => 1, 'page' => $page, 'cat' => 'cat=5 ' );
        $wp_query = new WP_Query($args);
        while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID;  ?>
                <div class="intro-noticia-4">
                    <a href="<?php the_permalink(); ?>">
                <?php $backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'large' );?>
                <div class="intro-post-thumbnail" style="background: url('<?php echo $backgroundImg[0]; ?>'); background-size: cover; background-position: center;">
                </div></a>
                </div>
        <?php endwhile; ?>

                <?php $page = (get_query_var('page')) ? get_query_var('page') : 1;
        $args = array( 'post_type' => 'post', 'posts_per_page' => 1, 'page' => $page, 'cat' => 'cat=6 ' );
        $wp_query = new WP_Query($args);
        while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID;  ?>
                <div class="intro-noticia-5">
                    <a href="<?php the_permalink(); ?>">
                <?php $backgroundImg = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'large' );?>
                <div class="intro-post-thumbnail" style="background: url('<?php echo $backgroundImg[0]; ?>'); background-size: cover; background-position: center;">
                </div></a>
            </div>
        <?php endwhile; ?>

Answer 1

You are adding post IDs to $do_not_duplicate, but you are missing the other half of the process- excluding those post IDs from subsequent queries. You can do that by setting post__not_in with the array of IDs you don't want returned.

$args = array(
    'posts_per_page' => 1,
    'paged' => $page,
    'cat' => 2,
    'post__not_in' => $do_not_duplicate,
);