Database
[{_id:1,"timestamp":ISODate("2022-11-03T15:00:00.000+00:00"),score:10},{_id:2,"timestamp":ISODate("2022-11-03T15:00:00.000+00:00"),score:13},{_id:3,"timestamp":ISODate("2022-11-03T10:00:00.000+00:00"),score:27},{_id:4,"timestamp":ISODate("2022-11-03T11:00:00.000+00:00"),score:26}]
Query
db.collection.aggregate([{$match:{$expr:{$gte:["$timestamp",{$dateAdd:{startDate:{$dateTrunc:{date:"$$NOW",unit:"hour"}},unit:"hour",amount:-1}}]}}}])