db={"incomeCash":[{"_id":"64d5fe21fb5b6271ce7934a1","buyer":{"title":"buyer1","key":"64234a2711d053037a0362d1"},"key":"64d5fe21fb5b6271ce7934a1",/**order 1 key*/"title":"ORDER 1","payments":[{"date":"2023-07-15T00:00:00.000Z","amount":"1.01"}],"total":"1.01","direction":"in"},{"_id":"6451db5cd001097cb1f27651","buyer":{"title":"buyer1","key":"64234a2711d053037a0362d1"},"key":"6451db5cd001097cb1f27651",/**order 2 key*/"title":"ORDER 2","payments":[{"date":"2023-05-08T00:00:00.000Z","amount":"1.01"},{"date":"2023-05-18T00:00:00.000Z","amount":"2.02"},{"date":"2023-07-15T00:00:00.000Z","amount":"3.03"}],"total":"6.06","direction":"in"}]}

db.incomeCash.aggregate([{$unwind:"$payments"},{$group:{_id:{buyerKey:"$buyer.key",date:{$toDate:"$payments.date"}},amount:{$sum:{$toDecimal:"$payments.amount"}},root:{$push:"$$ROOT"}}},{$unwind:"$root"},{$group:{_id:"$root._id",buyer:{$first:"$root.buyer"},key:{$first:"$root.key"},title:{$first:"$root.title"},payments:{$push:"$root.payments"},sumPayments:{$addToSet:{date:"$_id.date",amount:"$amount"}},total:{$first:"$root.total"},direction:{$first:"$root.direction"}}},{$group:{_id:"$buyer.key",title:{$first:"$buyer.title"},subLevels:{$addToSet:{key:"$key",title:"$title",payments:"$payments",total:"$total",direction:"$direction"}},total:{$sum:{$toDecimal:"$total"}},payments:{$push:"$sumPayments"}}},{$set:{subLevels:{$sortArray:{input:"$subLevels",sortBy:{"payment.date":1}}},payments:{$sortArray:{input:{$reduce:{input:"$payments",initialValue:[],in:{$let:{vars:{elem:{$concatArrays:["$$this","$$value"]}},in:{$setUnion:"$$elem"}}}}},sortBy:{date:1}}}}}])