How to count query results of entityQuery in drupal 8 & 9
To obtain a count query from an existing query, use the countQuery() method.
$count_query = $query->countQuery();
$count_query is now a new Dynamic Select query with no ordering restrictions that when executed will return a result set with only one value, the number of records that would be matched by the original query. Because PHP supports chaining methods on returned objects, the following idiom is a common approach:
$num_rows = $query->countQuery()->execute()->fetchField();
For an entity query (implementing QueryInterface), the code is slightly different:
$num_rows = $query->count()->execute();
Example How to count query results of entityQuery in drupal 8 & 9
$query = \Drupal::entityQuery('node')
->condition('type', 'page')
->condition('user_id', $user_id);
$count = $query->count()->execute();