[{"_id":1,"points":1,"monthly":[{"year":2021,"month":7,"points":1},{"year":1,"month":1,"points":1}]},{"_id":2,"points":1,"monthly":[{"year":1,"month":1,"points":1}]}]

db.collection.update({"_id":1,"monthly.year":2021,"monthly.month":7},{"$inc":{"points":5,"monthly.$.points":5}})