How to exclude product category?

Here is the code that removes the selected category from the list of products. I need the same thing from the plugin. If it helps.

function exclude_category_for_guests($query)
{
  if (! is_admin() && $query->is_main_query() && (is_shop() || is_product_category() || is_product())) {
    if (! is_user_logged_in()) {
      $tax_query = $query->get('tax_query');
      if (! empty($tax_query)) {
        $tax_query[] = array(
          'taxonomy' => 'product_cat',
          'field'    => 'slug',
          'terms'    => 'selected_category',
          'operator' => 'NOT IN',
        );
      } else {
        $tax_query = array(
          array(
            'taxonomy' => 'product_cat',
            'field'    => 'slug',
            'terms'    => 'selected_category',
            'operator' => 'NOT IN',
          ),
        );
      }
      $query->set('tax_query', $tax_query);
    }
  }
}
add_action('pre_get_posts', 'exclude_category_for_guests');