$node = Drupal::entityTypeManager()->getStorage('node')->load(123);

if ($node->getType() == 'application') {
  return $node;
} else {
  return false;
}

$nids = Drupal::entityQuery('node')
  ->condition('type', 'application')
  ->condition('nid', 123)
  ->execute();

// followed by entityTypeManager()->getStorage('node') etc.

$node = Drupal::entityTypeManager()->getStorage('node')->load(123);
if ($node instanceof DrupalnodeEntityNode && $node->getType() == 'application') {

}