Is there a way to add a ACF/metadata field data to a custom post type permalink?

Actually, for what you are trying to do, you do not need to manually add a new rewrite tag or rule.

If you want to change the permalink structure of a custom post type, then use the rewrite parameter for register_post_type() and set the rewrite slug to your preferred permalink structure, like so:

$args = array(
    'label'   => 'Books',
    'public'  => true,
    'rewrite' => array(
        // This means that the permalink URL would be
        // https://example.com/books/<ISBN>/<post slug>
        'slug' => 'books/%isbn%',
    ),
    // Your other args.
);

register_post_type( 'books', $args );

Then use the post_type_link hook to replace the %isbn% in the permalink with the correct value.

So looking at your code, you do not need this part: add_action( 'init', 'wpd_test_cpt' );, but you do need this: add_filter( 'post_type_link', 'wpd_test_post_type_link', 10, 2 );.

_{PS: Don’t forget to flush the rewrite rules after removing the unnecessary part above and changing the CPT’s rewrite slug.}