How not to cache part of the TWIG code ?

The following code is used to display whether the users are online, absent or offline.

My problem is that the current date "timestamp" is cached, so there is no change in user status unless I manually clear the cache with "drush cr".

How can I fix it ?

user--full.html.twig :

  {% if (date().timestamp - user.access.value) < 900 %}
    <div class="mt-2 text-center font-weight-bold font-italic text-success">
      <i class="fa fa-circle fa-lg"></i> Online
    </div>
  {% elseif (date().timestamp - user.access.value) < 1800 %}
    <div class="mt-2 text-center font-weight-bold font-italic text-warning">
      <i class="fa fa-circle fa-lg"></i> Absent
    </div>
  {% else %}
    <div class="mt-2 text-center font-weight-bold font-italic text-danger">
      <i class="fa fa-circle fa-lg"></i> Offline
    </div>
  {% endif %}

I found this code, but how do I use it with the user template to target only the user status (the code above) ?

bootstrap_subtheme_front_office_old.theme :

/**
 * User online status.
 */
function bootstrap_subtheme_front_office_old_preprocess_block(&$variables) {
  if ($variables['plugin_id'] == 'block_id') {
    $variables['#cache']['max-age'] = 0;
  }
}