WordPress: Display different styled featured posts without WP_Query.

featured_posts.php

<?php 
$fpi = 0; 
global $post; 

$featured_posts = get_posts( array( 
  'tag' => 'tag_as_you_want',   //tag that you want to select the posts
  'numberposts' => 5,           //how many posts
) );
if($featured_posts) { foreach ( $featured_posts as $post ) : setup_postdata( $post ); ?>
  
  <!-- looping content -->
  <?php if ($fpi == 0) : ?>

    <!-- first post in featured posts -->
    <article class="featured-big">
      <h2><?php the_title(); ?></h2>
    </article>
    <!-- first post in featured posts -->

  <?php else: ?>

    <!-- rest of the post -->
    <article class="featured-small">
      <h3><?php the_title(); ?></h3>
    </article>
    <!-- rest of the post -->

  <?php endif; $fpi++; ?>
  <!-- looping content -->

<?php endforeach; } wp_reset_postdata(); ?>