[{"licenseId":"3fa85f64-5717-4562-b3fc-2c963f66afa6","transactionDay":"2023-08-23","startTime":"2023-08-23T13:00:00Z","endTime":"2023-08-23T13:01:00Z","count":1,"size":12345}]

db.collection.aggregate([{$match:{"licenseId":"3fa85f64-5717-4562-b3fc-2c963f66afa6"}},{$group:{_id:"$transactionDay",licenseId:{$first:"$licenseId"},countTotal:{$sum:"$count"},sizeTotal:{$sum:"$size"}}},{$group:{_id:"$licenseId",transactionDays:{$push:{k:"$_id",v:{countTotal:"$countTotal",sizeTotal:"$sizeTotal"}}}}},{$project:{_id:0,licenseId:"$_id",usage:{$arrayToObject:"$transactionDays"}}}])