Constructing array of term reference labels in php template?
Following @4k4's suggestion to post the final code as an answer myself... here's the code that I'm now using and that seems to work well...

First of all, I defined a simple helper function:

function getTermName($term) {
  return($term-&gt;getName());
}


This allowed me to extend my code (see my original question above):

function hook_entity_view_mode_alter(&amp;$view_mode, Drupal\Core\Entity\EntityInterface $entity, $context) {
  ...
  $accesstags = array_map("getTermName", $entity-&gt;get('field_accesstags')-&gt;referencedEntities());
  if (in_array('subscription', $accesstags)) {
    ... allow access ...
  }
  ...
}


I'm still wondering, if there is a simpler way (without having to iterate over the array of terms), but for now the solution works well. Thanks again for your help, @4k4.