How can I add a ACF Block to the Gutenberg Detail Site-Structure

Question

I have the following ACF-Block (Akkordeon).

<?php
...

$anchor = '';
if (!empty($block['anchor'])) {
    $anchor = 'id="' . esc_attr($block['anchor']) . '" ';
}

$class_name = 'accordion-block';
if (!empty($block['className'])) {
    $class_name .= ' ' . $block['className'];
}

?>

<div class="<?php echo esc_attr($class_name); ?>">
    <h3 <?php echo $anchor; ?> class="accordion-element accordion">
        <?php the_field('accordion-title'); ?>
    </h3>
    <div class="accordion-panel">
        <InnerBlocks />
    </div>
</div>

I use the InnerBlocks element within the content area of ​​the accordion, there I can insert any Gutenberg block. If I insert a Gutenberg heading within this area, it is displayed in the structure, but not the h3 from the accordion title.

I want to add the h3 (accordion title) to the Gutenberg Detail Site-Structure. (picture)