[{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1602,last_modified:2},{item:{id:168652},connected_realm_id:1602,last_modified:3},{item:{id:168652},connected_realm_id:1602,last_modified:4},{item:{id:168652},connected_realm_id:1602,last_modified:5},{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1602,last_modified:1596719280},{item:{id:168652},connected_realm_id:1603,last_modified:1596719267},{item:{id:168652},connected_realm_id:1603,last_modified:1596719267},{item:{id:168652},connected_realm_id:1603,last_modified:1596719267},{item:{id:168652},connected_realm_id:1603,last_modified:1596719267},{item:{id:168652},connected_realm_id:1603,last_modified:1},{item:{id:168652},connected_realm_id:1603,last_modified:2},{item:{id:168652},connected_realm_id:1603,last_modified:3},{item:{id:168652},connected_realm_id:1603,last_modified:4},{item:{id:168652},connected_realm_id:1603,last_modified:5},{item:{id:168652},connected_realm_id:1603,last_modified:1596719267}]

db.collection.aggregate([{$group:{_id:{connected_realm_id:"$connected_realm_id"},latest:{$max:"$last_modified"},data:{$push:"$$ROOT"}}},{$unwind:"$data"},{$addFields:{"data.latest":{$cond:{if:{$eq:["$data.last_modified","$latest"]},then:"$latest",else:"$false"}}}},{"$replaceRoot":{"newRoot":"$data"}},{"$match":{"latest":{"$exists":true,"$ne":null}}}])