prevent.php

function fut_content_preprocess_field(&$variables) {
  $element = $variables['element'];
  if ($element['#field_type'] == 'comment') {
    if (_fut_content_prevent_comments()) {
      unset($variables['comment_form']);
    }
  }
}

function fut_content_comment_links_alter(array &$links, CommentInterface $entity, array &$context) {
  if (_fut_content_prevent_comments()) {
    unset($links["comment"]["#links"]["comment-reply"]);
  }
}

function _fut_content_prevent_comments() {
  $current_user = \Drupal::currentUser();
  $group = \Drupal::service('fut_group.request_entity_extractor')->getGroup();
  $prevent = isset($group) && !$group->hasPermission('comment group content', $current_user);
  return $prevent;
}