[{"_id":1,"year":2021,"movies":2000},{"_id":2,"year":2020,"movies":3000},{"_id":3,"year":2019,"movies":2000},{"_id":4,"year":2018,"movies":2000},{"_id":5,"year":2017,"movies":1500},{"_id":6,"year":2016,"movies":1000}]

db.collection.aggregate([{"$setWindowFields":{"output":{"dense-rank":{"$denseRank":{}}},"sortBy":{"movies":-1}}},{"$match":{"$expr":{"$lte":["$dense-rank",3]}}},{"$unset":["dense-rank"]}])