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.users.aggregate([{$lookup:{from:"partnership",let:{user_id:"$_id"},pipeline:[{$match:{$expr:{$eq:["rrr",{$arrayElemAt:["$users",1]}]}}}],as:"valid"}},{$match:{"valid.0":{$exists:true},location:{$exists:true}}},{$sort:{calculatedDist:1}},{$unset:["location","calculatedDist","valid"]},{$group:{_id:0,users:{$push:"$$ROOT"},count:{$sum:1}}}])