Register CPT endpoint

<?php
if ( ! defined( 'ABSPATH' ) ) exit;

add_action('rest_api_init', function () {
    register_rest_route('referenciak', '/v1', [
        'methods'  => 'GET',
        'callback' => 'get_referenciak_all',
        'permission_callback' => '__return_true',
    ]);
});


function get_referenciak_all(WP_REST_Request $request) {
    $query = new WP_Query([
        'post_type'              => 'referenciak',
        'post_status'            => 'publish',
        'posts_per_page'         => -1,
        'orderby'                => 'menu_order',
        'order'                  => 'ASC',
        'no_found_rows'          => true,
        'update_post_meta_cache' => true,
        'update_post_term_cache' => true,
    ]);

    $references = [];

    foreach ($query->posts as $post) {
        $terms = get_the_terms($post->ID, 'referencia-kategoria');

        if (is_wp_error($terms) || empty($terms)) {
            $terms = [];
        }

        $references[] = [
            'title'          => get_the_title($post),
            'featured_image' => get_the_post_thumbnail_url($post, 'full') ?: null,
            'taxonomy'       => array_values(array_map(function ($term) {
                return [
                    'id'   => (int) $term->term_id,
                    'name' => $term->name,
                    'slug' => $term->slug,
                ];
            }, $terms)),
        ];
    }

    return rest_ensure_response($references);
}