The use of indexes should be taken carefully, it has a price in the creation of the item.
By the way, I would like to understand if it is possible to do .group(“_createdDate”)
Because the information contains, in addition to the day, also an hour and seconds, then the attempt to accumulate, for example, all the donations on the same day is ineffective.
The solution I see is to add a hook that will create another field with the new field type, which is just a date without a time. (big headache all these WIX changes)