Permalinks with custom post type and taxonomy category

Hello, i am a french beginner developer in WordPress and i am doing a site for an artist. So i created a custom post type “portfolio” like this :

register_post_type('portfolio', [
'labels' => [
'name' => 'Portfolio',
'show_ui' => true,
'singular_name' => 'Portfolio Item',
],
'public' => true,
'has_archive' => true,
'supports' => ['title', 'thumbnail', 'editor'],
'rewrite' => ['slug' => 'portfolio'],
'menu_icon' => 'dashicons-format-gallery'
]);
}
add_action('init', 'gbl_post_types');

Then a taxonomy which allows to create categories and sub-categories to my portfolio, in fact 2 parent category and also sub-category, for example (photographie/portrait), so i created this :

function create_portfolio_taxonomy() {
$labels = array(
'name' => _x( 'Catégories Portfolio', 'taxonomy general name' ),
'singular_name' => _x( 'Catégorie Portfolio', 'taxonomy singular name' ),
'all_items' => ( 'Toutes les Catégories' ), 'parent_item' => ( 'Parent Catégorie Portfolio' ),
'parent_item_colon' => ( 'Parent Catégorie Portfolio:' ), 'edit_item' => ( 'Editer une Catégorie Portfolio' ),
'update_item' => ( 'Mettre à jour une Catégorie Portfolio' ), 'add_new_item' => ( 'Ajouter une Catégorie du Portfolio' ),
'new_item_name' => ( 'Nouvelle Catégorie Portfolio' ), 'menu_name' => ( 'Catégories du Portfolio' ),
);
$args = array(
'hierarchical' => true,
'labels' => $labels,
'public' => true,
'show_ui' => true,
'has_archive' => true,
'show_in_rest' => true,
'show_admin_column' => true,
'query_var' => true,
'rewrite' => array( 'slug' => 'portfolio-category' ),
);
register_taxonomy( 'portfolio_category', array( 'portfolio' ), $args );
}
add_action( 'init', 'create_portfolio_taxonomy' );

And i display first my 2 parent categories with the “archive-portfolio.php” template then the sub-categories of a parent category with the “taxonomy-portfolio_category.php” template and the template for display one item of my portfolio is “single-portfolio.php” I would like the permalinks to be good by displaying like that : “my-site/portfolio/category/sub-category/post-title, for example : my-site/portfolio/photographie/portrait-of-woman-in-the-street.

So the problem comes from my taxonomy-portfolio_category.php code:

<div class="works-col col-xs-12 col-sm-6 col-md-6 col-lg-6 <?php foreach ($categories as $category) { echo get_sorting_class($category->name) . ' '; } ?>">
    <div class="works-item scrolla-element-anim-1 scroll-animate" data-animate="active">
        <?php
        $parent_category = null;
        $sub_category = null;

        // Find the parent and sub-category terms
        foreach ($categories as $category) {
            if ($category->parent == 0) {
                $parent_category = $category;
            } else {
                $sub_category = $category;
            }
        }

        if ($parent_category) {
            $parent_category_slug = sanitize_title($parent_category->slug);
        } else {
            $parent_category_slug = '';
        }

        if ($sub_category) {
            $sub_category_slug = sanitize_title($sub_category->slug);
        } else {
            $sub_category_slug = '';
        }

        $portfolio_item_slug = sanitize_title(get_the_title());

        // Construct the correct link based on hierarchy
        $link = home_url("/portfolio/$parent_category_slug");
        if (!empty($sub_category_slug)) {
            $link .= "/$sub_category_slug";
        }
        $link .= "/$portfolio_item_slug/";
        ?>
        <a href="<?php echo esc_url($link); ?>">
<span class="image">
                                <span class="img">
                                    <img src="<?php echo esc_url($thumbnail_url); ?>" alt="<?php the_title_attribute(); ?>" />
                                </span>
                            </span>
                            <span class="desc">
                                <span class="category splitting-text-anim-4 scroll-animate" data-splitting="chars" data-animate="active">
                                <?php
                                    $category_names = array();
                                    // Sort categories by term ID to ensure consistent order
                                    usort($categories, function ($a, $b) {
                                        return $a->term_id - $b->term_id;
                                    });
                                    foreach ($categories as $category) {
                                        $category_names[] = esc_html($category->name);
                                    }
                                    echo implode(' - ', $category_names);
                                    ?>
                                </span>
                            </span>
                        </a>
                    </div>
                </div>

This code should construct the permalink with the parent category, sub-category, and post title but still not good, i have my-site/portfolio/photographie/photographie-beyrouth/beyrouth-1/ , that is to say /portfolio/parent-category-name/sub-category-slug/post-title and it should be my-site/portfolio/photographie/beyrouth/beyrouth-1/ that is to say /portfolio/parent-category-name/sub-parent-category-name/post-title, so in fact just sub-parent-category-name should be display instead of sub-parent-category-slug-name.

After that i have installed the plugin Custom Post Type Permalinks,and configure Custom structure for ‘portfolio’: /portfolio/%portfolio_category%/%postname%/ but still not working good.

So i do not know if WordPress does not support hierarchical taxonomies with the exact structure you’re trying to achieve.

In this situation, achieving such a permalink structure might require customizing the rewrite rules at a deeper level, which can be quite complex. But I don’t think this type of site is so unusual, on the contrary there are plenty of configurations where you have to have a CPT with categories and subcategories?

Thank you !