Using COUNT on groupBy

To get submission's statistics on a given element of a webform I'm using the following query.

public function getElementSubmissionsStatistics($elementID): array {
    $db = \Drupal::database();
    $query = $db->select('webform_submission_data', 'wsd');
    $query->fields('wsd', ['value', 'name']);
    $query->addExpression('COUNT(value)', 'quantity');
    $query->condition('wsd.webform_id', $this->webform->id());
    $query->condition('name', $elementID);
    $query->groupBy('wsd.value');
    $records = (array) $query->execute()->fetchAllAssoc('value');

    $values = [];

    $totalQuantity = (int) array_sum(array_column($records,'quantity'));;

    foreach ($records as $key => $record) {
      $values[$key]['quantity'] = (int) $record->quantity;
      $values[$key]['percentage'] = (float) $record->quantity / $totalQuantity;
      $values[$key]['value'] = (string) $record->value;
    }
 
    $this->elementsStatistics[$elementID] = $values;
    return $this->elementsStatistics[$elementID];

}

I'm using this on radio element (but should works on any element) to count the number of time an option was selected.

It work well but I wanted to add some condition to filter my query on other webform's field values. Webform query seem to greatly simplify this. But if I'm not mistaken it doesn't provide a way to group_by and count.

I need to load all the submission and do this in PHP? Or is they another option?

Would it be possible to support COUNT and groupBy in the future?