pre_get_posts.php

function offset_blog_posts($query)
{
    if ($query->is_home() || $query->is_category() && $query->is_main_query() && !is_admin()) {

        $post_type = array('post');

        $query->set('post_type', $post_type);
        $query->set('post_status', 'publish');
        $query->set('ignore_sticky_posts', '-1');

        $ppp = get_option('posts_per_page');
        $offset = 1;

        if (!$query->is_paged()) {
            $query->set('posts_per_page', $offset + $ppp);
        } else {
            $offset = $offset + ( ($query->query_vars['paged']-1) * $ppp );
            $query->set('posts_per_page',$ppp);
            $query->set('offset',$offset);
        }
    }
}
add_action('pre_get_posts','offset_blog_posts')

Wordpress-loops.php

<?php
get_header();

// Used for the subnav bar so it knows what to pull through
$catArgs = ['hide_empty' => 1, 'type' => 'post'];
$categories = get_categories($catArgs);

// used for managing the display of categories
$curCat = get_the_category();
$curCategoryName = single_cat_title("", false);

$catCount = $curCat[1]->count-1;

if ($curCategoryName === 'All') {
	$catID = $curCat[0]->cat_ID;
} else {
	$catID = $curCat[1]->cat_ID;
}

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;


$do_not_duplicate = '';

remove_action('pre_get_posts', 'offset_blog_posts');
?>

<?php if($paged == 1): ?>
	<?php
		global $post;
		$args = array(
			'numberposts' => 1,
			'offset'=> 0,
			'category' => 1
		);
		$firstPost = get_posts( $args );
		foreach( $firstPost as $post ) :  setup_postdata($post); ?>
			<?php
				$do_not_duplicate = $post->ID;

				if (has_post_thumbnail($post->ID) ); {
					$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'large' );
				}
			?>
			<header class="b-hero hero" style="background-image: url('<?php echo $image[0]; ?>');" height="<?php echo $image[2]; ?>">
				<a class="hero__link" href="<?php the_permalink(); ?>">
					<time class="hero__date"><?php the_time('d . m . y'); ?></time>
					<h1 class="hero__title"><?php the_title(); ?></h1>
					<p class="hero__read-more">Read More</p>
				</a>
				<div class="hero__overlay"></div>
			</header>
		<?php endforeach; ?>

	<?php wp_reset_postdata(); ?>
<?php endif; ?>

<div class="subBar">
	<div class="subBar__inner">
		<ul class="subBar__list">
			<?php foreach ($categories as $category): ?>

				<?php $activeClass = ($category->name === $curCategoryName ? 'subBar__links--active' : '' ) ; ?>

				<li class="subBar__items">
					<?php if ($category->name === 'All'): ?>
						<a class="subBar__links <?php echo $activeClass; ?>" href="<?php echo home_url('/blog'); ?>"><?php echo $category->name; ?></a>
					<?php else: ?>
						<a class="subBar__links <?php echo $activeClass; ?>" href="<?php echo get_category_link( $category->cat_ID ); ?>"><?php echo $category->name; ?></a>
					<?php endif; ?>
				</li>

			<?php endforeach; ?>
		</ul>
	</div>
</div>

<div class="blogListing">
	<div class="blogListing__inner">
		<?php add_action('pre_get_posts', 'offset_blog_posts'); ?>
		<?php if ( have_posts() ) : ?>
			<?php;
				$published_posts = ( !is_category() ? wp_count_posts('post')->publish : $catCount);
				$posts_per_page = get_option('posts_per_page');
				$page_number_max = ceil($published_posts / $posts_per_page);
				$nextPage = get_next_posts_page_link();

				wp_localize_script(
					'script',
					'post_ajax', [
						'postType' => get_post_type(),
						'maxPages' => $page_number_max,
						'nextPage' => $nextPage
					]
				);
			?>

			<?php while ( have_posts() ) : the_post(); ?>
				<?php
					// get the post ID
					$id = get_the_ID();

					// pass this is equal to the first blog post
					if ($id === $do_not_duplicate ) {
						continue;
					}

					// get our thumbnail image
					$image = (has_post_thumbnail( $id ) ? wp_get_attachment_image_src( get_post_thumbnail_id( $id ), 'large' ) : null );

					// category info for each article
					$category = get_the_category( $id );
					$catnames = [];
					foreach ($category as $cat) {
						if ($cat->slug !== 'all') {
							array_push($catnames, $cat->name);
						}
					}
				?>

				<article class="blogListing__content" role="article">
					<a class="blogListing__linkWrap" href="<?php the_permalink(); ?>">
						<img class="blogListing__img lazy" data-cslayzr="<?php echo $image[0]; ?>"  draggable="false" />
						<noscript><img class="blogListing__img lazy" src="<?php echo $image[0]; ?>"  draggable="false" /></noscript>
						<small class="blogListing__category"><?php foreach ($catnames as $catname) { echo $catname; } ?></small>
					</a>
					<div class="bloglisting__info">
						<time class="blogListing__date"><?php the_time('d . m . y'); ?></time>
						<a class="blogListing__linkWrap" href="<?php the_permalink(); ?>">
							<h2 class="blogListing__title"><?php the_title(); ?></h2>
						</a>
						<p class="blogListing__shortDescription"><?php echo substr(preg_replace("/&#?[a-z0-9]+;/i", "", get_the_excerpt()), 0, 90); ?>...</p>
					</div>
				</article>
			<?php endwhile; ?>
		<?php endif; ?>
	</div>
</div>

<div class="spinner" role="presentation">
	<div class="spinner__inner">
		<span class="spinner__dot"></span>
	</div>
</div>

<?php get_footer(); ?>