Elimina los registros de un tipo de contenido en drupal

Metodo 1

ss$result = \Drupal::entityQuery("node")
    ->condition("type", "YOUR_CONTENT_TYPE_NAME")
    ->accessCheck(FALSE)
    ->execute();

$storage_handler = \Drupal::entityTypeManager()->getStorage("node");
$entities = $storage_handler->loadMultiple($result);
$storage_handler->delete($entities);

Metodo 2

$storage_handler = \Drupal::entityTypeManager()->getStorage("node");
$entities = $storage_handler->loadByProperties([
  "type" => "YOUR_CONTENT_TYPE_NAME",
]);
$storage_handler->delete($entities);

<?php

/**
* Elimina Registros de un determinado Content Type.
*
* @param array $types Areglo de content types(machine_name)
* ejemplo: ['content_type_01', 'content_type_02']
* @param boolean $delete_log limpiar log true/false.
*/
public function eliminarNodos(array $types, $delete_log =false)
{
    foreach ($types as $type) {
        $sql = 'SELECT nid FROM {node} n WHERE n.type = :type';
        $result = db_query($sql, array(':type' => $type));
        foreach ($result as $row) {
            $node = \Drupal\node\Entity\Node::load($row->nid);
            if ($node) {
                $node->delete();
            }
        }
        field_purge_batch(1000);
    }
    if ($delete_log) {
        db_query(' TRUNCATE TABLE {watchdog} ');
    }
}