What is considered most efficient when deleting a Firestore collection?

Performing deletions using batches:

async function deleteCollection(db, collectionPath, batchSize) {
  const collectionRef = db.collection(collectionPath);
  const query = collectionRef.orderBy('__name__').limit(batchSize);

  return new Promise((resolve, reject) => {
    deleteQueryBatch(db, query, resolve).catch(reject);
  });
}

async function deleteQueryBatch(db, query, resolve) {
  const snapshot = await query.get();

  const batchSize = snapshot.size;
  if (batchSize === 0) {
    // When there are no documents left, we are done
    resolve();
    return;
  }

  // Delete documents in a batch
  const batch = db.batch();
  snapshot.docs.forEach((doc) => {
    batch.delete(doc.ref);
  });
  await batch.commit();

  // Recurse on the next process tick, to avoid
  // exploding the stack.
  process.nextTick(() => {
    deleteQueryBatch(db, query, resolve);
  });
}

Or using the firestore's default recursiveDelete() method:

await firestore.recursiveDelete(collectionRef);

Note: The collection I am trying to delete doesn't have nested sub-collections. Also, I am running this code in a cloud function.

/messages (C)
  -message_id_1 (D)
  -message_id_2 (D)
  -message_id_3 (D)
  ...
  -message_id_10000 (D)