Eigenes Theme wandelt keine Shortcodes um

<?php
if(have_posts())
{
    global $post;
    $args = array("numberposts" => 3, "category_name" => "Featured_Post_Top");
    $posts = get_posts($args);
        
    foreach    ($posts as $post)
    {
        $theme_path = get_template_directory_uri();
        $content = $post->post_content;
        $author = get_author_name($post->post_author);
        $title = $post->post_title;
        $thumbnail_id = get_post_thumbnail_id($post->ID);
        $thumbnail_src = wp_get_attachment_image_src($thumbnail_id, "full")[0];


        echo "<div class='featured'>";
        echo "<div id='header'>";
        echo "<img src='".$theme_path."/Image/Header.png' width='100%' height='100%' />";
        echo "<div id='headline'><a href='".get_permalink($post->ID)."'>".$title."</a></div>";
        echo "</div>";
        echo "<div id='thumbnail'>";
        if(has_post_thumbnail($post->ID))
        {
            echo "<img src='".$thumbnail_src."' width='100%' height='100%' />";
        }
        else
        {
            echo "<img src='".$theme_path."/Image/ArticleImage.jpg' width='100%' height='100%' />";
        }
        echo "</div>";
        echo "<div id='content'>";
        echo substr($content,0, 150)."...";
        echo "</div>";
        echo "<img src='".$theme_path."/Image/Articlefooter.jpg' width='100%' />";
        echo "</div>";
    }
}
?>