db={partnership:[{_id:"xyz_rrr",updated:"2022-10-23T12:35:24.772+00:00",users:["xyz","rrr"]},{_id:"rrr_eee",updated:"2023-01-23T12:35:24.772+00:00",users:["rrr","eee"]},{_id:"eee_rrr",updated:"2023-01-21T12:35:24.772+00:00",users:["eee","rrr"]},{_id:"mmm_rrr",updated:"2023-02-19T12:35:24.772+00:00",users:["mmm","rrr"]},{_id:"rrr_mmm",updated:"2023-02-21T12:35:24.772+00:00",users:["rrr","mmm"]},],users:[{_id:"abc",name:"abc",},{_id:"xyz",name:"xyyy",},{_id:"123",name:"yyy",},{_id:"rrr",name:"rrrrrrr",},{_id:"mmm",name:"mmmm",},{_id:"eee",name:"eeeee",}],}

db.partnership.aggregate([{$set:{partitionKey:{"$reduce":{"input":{$sortArray:{input:"$users",sortBy:1}},"initialValue":"","in":{"$concat":["$$value","$$this"]}}}}},{"$setWindowFields":{"partitionBy":"$partitionKey","sortBy":{"updated":-1},"output":{"count":{$sum:1},rank:{$rank:{}}}}},{$match:{count:{$gt:1},rank:1}},{"$lookup":{"from":"users","localField":"users","foreignField":"_id","as":"userLookup"}},{"$project":{_id:0,partneredUsers:{firstUser:{$first:"$userLookup"},secondUser:{$last:"$userLookup"}},partneredDate:"$updated"}},{$sort:{partneredDate:-1}}])