[{"startDate":ISODate("2023-09-30T11:00:00Z")},{"startDate":ISODate("2024-09-30T11:00:00Z")},{"startDate":ISODate("2025-09-30T11:00:00Z")}]

db.collection.aggregate([{"$match":{$expr:{$eq:[{$dateTrunc:{date:"$startDate",unit:"day"}},{$dateTrunc:{date:"$$NOW",unit:"day"}}]}}}])