[{_id:ObjectId("623e4a91e9bdcf156119450f"),name:"aboba1",number:1},{_id:ObjectId("622e4a91e9bdcf156119450f"),name:"aboba2",number:2},{_id:ObjectId("611e4a91e9bdcf156119450f"),name:"aboba3",number:3}]

db.collection.aggregate([{"$sort":{"updated_at":-1}},{"$group":{"_id":"$_id","doc":{"$first":"$$ROOT"}}},{"$replaceRoot":{"newRoot":"$doc"}},{"$project":{"_id":{"$toString":"$_id"}}}])