[SOLVED] Use Query.between() to list documents by date

    String today = DateTime.now().toString().substring(0, 10); // YYYY-MM-DD
    String oneMonthAgo = DateTime.now().subtract(Duration(days: 30)).toString().substring(0, 10);
...
  dataMonth = database.listDocuments(
        databaseId: databaseId,
        collectionId: collectionId,
        queries: [
          Query.between(
              '\$createdAt',
              oneMonthAgo,
              today),
        ]
...
  context.log("Documents");
      dataMonth.documents.every(
        (element) {
          context.log(element.data['data']);
          return true;
        },
      ); 
// Printed 1 document, expected 3 documents

    String today = DateTime.now().add(Duration(days: 1)).toString().substring(0, 10);
    String oneMonthAgo = DateTime.now().subtract(Duration(days: 31)).toString().substring(0, 10);