Is it possible to disable cache on certain fields?
You need to adjust the cache context of the node.

If the cookie is a drupal session, use the predefined cache context for this:

$build['#cache']['contexts'][] = 'session.exists';


If you target another cookie, that drupal is not aware of, you would need to create your own context, more info:

https://www.drupal.org/developing/api/8/cache/contexts