[{"_id":1,"name":"John","age":25,"valid_user":true},{"_id":2,"name":"Bob","age":40,"valid_user":false},{"_id":3,"name":"Jacob","age":27,"valid_user":null},{"_id":4,"name":"Amelia","age":29,"valid_user":true}]

db.collection.aggregate([{"$facet":{"user_by_valid_status":[{"$group":{"_id":"$valid_user","count":{"$sum":1}}},{$project:{_id:0,v:{_id:"$_id",count:"$count"},k:{$switch:{branches:[{case:{$eq:["$_id",null]},then:"user_with_unknown_status"},{case:{$eq:["$_id",false]},then:"invalid_user"},{case:{$eq:["$_id",true]},then:"valid_user"}]}}}}],"users_above_30":[{"$match":{"age":{"$gt":30}}}]}},{$project:{analytics:{$arrayToObject:"$user_by_valid_status"},users_above_30:1}}])