Database
[{"key":1}]
Query
db.collection.aggregate([{"$addFields":{"dateField":ISODate("2022-03-28")}},{"$project":{"dayOfMonth":{"$dayOfMonth":"$dateField"},"wks_sunday":{"$dateDiff":{startDate:ISODate("2022-03-01"),endDate:"$dateField",unit:"week",startOfWeek:"sunday"}},"wks_saturday":{"$dateDiff":{startDate:ISODate("2022-03-01"),endDate:"$dateField",unit:"week",startOfWeek:"saturday"}}}},{"$project":{"_id":0,"daysUtil":{"$subtract":["$dayOfMonth",{"$sum":["$wks_sunday","$wks_saturday"]}]}}}])