db={"t_credentials":[{"_id":"619ca68b624c41e408348406","title":"Company ID"}],"t_groups":[{"_id":"61a253da88ca12a37218898d","group_name":"Gold"}],"t_user_credentials":[{"_id":"619ca88a624c41e408348424","credential_id":"619ca68b624c41e408348406","group_id":"61a253da88ca12a37218898d","identifiers":{"first_name":"Lee","middle_name":"Min","last_name":"Ho"},"created_at":"2021-12-01T17:20:49.000Z"}]}

db.t_user_credentials.aggregate([{"$lookup":{"from":"t_credentials","localField":"credential_id","foreignField":"_id","as":"credential"}},{"$lookup":{"from":"t_groups","localField":"group_id","foreignField":"_id","as":"group"}},{$unwind:"$group",},{$unwind:"$credential"},{$replaceWith:{$mergeObjects:["$$ROOT","$identifiers"]}},{$unset:["group_id","credential_id","identifiers"]}])