[{"dateTime":ISODate("2020-06-03"),"value":25},{"dateTime":ISODate("2020-05-25"),"value":27}]

db.collection.aggregate([{"$match":{"dateTime":{"$gte":ISODate("2020-05-01"),"$lte":ISODate("2020-07-01")}}},{"$group":{"_id":{"week":{"$isoWeek":{"date":"$dateTime","timezone":"+00:00"}},"year":{"$isoWeekYear":{"date":"$dateTime","timezone":"+00:00"}}},"maxValue":{"$max":"$value"}}},{"$project":{"_id":{"start":{"$dateToString":{"date":{"$dateFromParts":{"isoWeekYear":"$_id.year","isoWeek":"$_id.week"}},"format":"%Y-%m-%d"}},"end":{"$dateToString":{"date":{"$add":[{"$dateFromParts":{"isoWeekYear":"$_id.year","isoWeek":"$_id.week"}},518400000]},"format":"%Y-%m-%d"}}},"maxValue":"$maxValue"}}])