[{userId:"6udg",last_seven_day_arr:[{date:"22-09-2022",hits:98},{date:"23-09-2022",hits:88},{date:"24-09-2022",hits:100}],last_month_arr:[{date:"04-09-2022",hits:98},{date:"12-09-2022",hits:88},{date:"13-09-2022",hits:100},{date:"14-09-2022",hits:100},{date:"14-09-2022",hits:100}],last_year_arr:[{date:"22-07-2022",hits:98},{date:"23-07-2022",hits:88},{date:"24-07-2022",hits:100},{date:"14-06-2022",hits:100},{date:"14-06-2022",hits:100},{date:"14-08-2022",hits:100},{date:"14-08-2022",hits:100}]}]

db.collection.aggregate([{$project:{last_seven_day:{data:"$last_seven_day_arr",avg:{$avg:"$last_seven_day_arr.hits"}},last_month:{data:"$last_month_arr",avg:{$avg:"$last_month_arr.hits"}},last_year:{data:"$last_year_arr",avg:{$avg:"$last_year_arr.hits"}}}}])