add some code before second h2

Hi there!
Guys, I have wrote some code and it adding some code )) before second h2, but it works only for classic editor’s posts.
How to make it correct for advanced editor’s posts?

add_filter( 'the_content', 'prefix_insert_post_ads' );

function prefix_insert_post_ads( $content ) {

    $ad_code = '<div style="display: flex; gap: 0.5rem;">
  				<div class="column"><a href="#"><img src="/uploads/2023/07/banner_fin_1.jpg" alt="image" /></a></div>
    				<div class="column"><a href="#"><img src="/uploads/2023/07/banner_fin_2.jpg" alt="image" /></a></div>
    				<div class="column"><a href="#"><img src="/uploads/2023/07/banner_fin_3.jpg" alt="image" /></a></div>
</div>';

    if ( is_single() && ! is_admin() && in_category('152') ) {
        return prefix_insert_after_paragraph( $ad_code, 1, $content );
    }

    return $content;
}

	
function prefix_insert_after_paragraph( $insertion, $paragraph_id, $content ) {
    $closing_p = '<h2>';
    $paragraphs = explode( $closing_p, $content );
    if ($paragraphs) {
        $paragraphs[1] = $paragraphs[1].$insertion;
    }    
    return implode( '<h2>', $paragraphs );
}

Thank you!