Convert WordPress shortcodes into plain html

Question

First of all, you have a syntax error. If your shortcode is stored in the $output variable, you would need to call echo do_schortcode($output);.

But, wouldn’t simply the_content(); do the trick? I believe the shortcodes would be processed if you do this.

You can make a new query with WP_Query, and then use the_content() in the loop.

$args = array(
  'post_type' => 'post', // This selects only posts
  'post_status' => 'publish' // Only published posts
);
// The Query
$the_query = new WP_Query( $args );

// The Loop
if ( $the_query->have_posts() ) {
    echo '<ul>';
    while ( $the_query->have_posts() ) {
        $the_query->the_post(); ?>
        <li><?php the_content(); ?></li>
    <?php }
    echo '</ul>';
    /* Restore original Post Data */
    wp_reset_postdata();
} else {
    // no posts found
}