Database
[{date:"2022-07-09",/**YYYY-MM-DD*/amount:54.77},{date:"2022-07-21",amount:50.20},{date:"2022-07-21",amount:50.20},{date:"2022-06-26",amount:54},{date:"2022-06-06",amount:37},{date:"2022-06-06",amount:37},{date:"2022-06-09",amount:51.77}]
Query
db.collection.aggregate([{$group:{_id:{month:{$substr:["$date",5,2]},year:{$substr:["$date",0,4]}},amount:{$sum:"$amount"},transactions:{$push:"$$ROOT"}}}])