db={"users":[{_id:ObjectId("61e9536f142f337c96883c52"),name:"John",phone:"(222) 123-4568"},{_id:ObjectId("61e9536f142f337c96800a56"),name:"Bob",phone:"(200) 123-4568"}],"routes":[{routes:[{driver_id:ObjectId("61e9536f142f337c96883c52"),route_id:"SRT006",payment:13.2},{driver_id:ObjectId("61e9536f142f337c96800a56"),route_id:"SRT005",payment:15},{route_id:"SRT004",payment:20}],apartment:"abc apartment",deliverydate:"06/03/2022"}]}

db.routes.aggregate([{"$unwind":"$routes"},{"$lookup":{"from":"users","localField":"routes.driver_id","foreignField":"_id","as":"driver"}},{"$addFields":{"driver":{"$arrayElemAt":["$driver",0]}}},{"$addFields":{"routes.driver_name":"$driver.name"}},{"$project":{driver:0}},{"$group":{"_id":"$_id","routes":{"$push":"$routes"}}}])