How do I differentiate between menu items with and without subnavigation?

Kirby 3 Solved ✅
3

Thanks for your code adjustment. I had also received a syntax error and could not find the error. In order not to get stuck, I had ChatGPT check the code. Now the menu works as it should. Here is the corrected code:
(To keep the code clearer, I removed some CSS classes).

<?php
$items = $pages->listed();
if ($items->isNotEmpty()):
?>

<ul class="menu-list">
<?php foreach ($items as $item): ?>
    <?php $children = $item->children()->listed(); ?>
    <?php if ($children->isEmpty()): ?>
        <li class="menu-list-item <?php e($item->isOpen(), 'active') ?>">
            <a href="<?= $item->url() ?>"><?= $item->title()->html() ?></a>
        </li>
    <?php else: ?>
        <li class="menu-list-item">
            <a href="javascript:void(0);"><?= $item->title()->html() ?></a><span class="menu-toggle"></span>
            <ul class="sub-menu-item">
                <?php foreach ($children as $child): ?>
                    <li class="<?php e($child->isOpen(), 'active') ?>">
                        <a href="<?= $child->url() ?>"><?= $child->title()->html() ?></a>
                    </li>
                <?php endforeach ?>
            </ul>
        </li>
    <?php endif ?>
<?php endforeach ?>
</ul>
<?php endif ?>