Add meta noindex to post if it has a specific taxonomy

You can use the wp_robots filter to manipulate the robots meta tag as needed. And as you’re checking against a taxonomy term you can use the has_term() helper conditional to make your code look a litte nicer. (A post can be passed to has_term() as the 3rd parameter, but if it is not passed then the function checks against the current post.)

add_filter(
    'wp_robots',
    function(array $robots) {
        if ( has_term('enviso_group_ticket', 'product_type') ) {
            return array_merge(
                $robots,
                array(
                    'noindex' => true,
                    'nofollow' => true,
                )
            );
        } else {
            return $robots;
        }
        
    }
);