Database
[{"deviceId":"1106","orgId":"5ffe9fe1c9e77c0006f0aad3","values":[{"paramVal":105.0,"dateTime":ISODate("2021-05-05T09:18:08.000Z")},{"paramVal":110.0,"dateTime":ISODate("2021-05-05T09:18:08.000Z")},{"paramVal":115.0,"dateTime":ISODate("2021-05-05T10:18:08.000Z")},{"paramVal":125.0,"dateTime":ISODate("2021-05-05T11:18:08.000Z")},{"paramVal":135.0,"dateTime":ISODate("2021-05-05T12:18:08.000Z")}]}]
Query
db.collection.aggregate([{$unwind:"$values"},{$sort:{"values.dateTime":-1}},{$group:{_id:"$_id",deviceId:{$first:"$deviceId"},orgId:{$first:"$orgId"},values:{$push:"$values"}}},{$set:{values:{$slice:["$values",2]}}}])