Database
[{todos:[{task:{type:"someType",},dueDate:"2021-04-30T18:30:00.000Z",},{task:{type:"someType",},dueDate:"2021-02-30T18:30:00.000Z",},{task:{type:"someType",},dueDate:"2021-01-30T18:30:00.000Z",},],},{todos:[{task:{type:"someType",},dueDate:"2021-01-30T18:30:00.000Z",},{task:{type:"someType",},dueDate:"2021-03-29T18:30:00.000Z",},{task:{type:"someType",},dueDate:"2021-01-30T18:30:00.000Z",},],}]
Query
db.collection.aggregate([{"$unwind":"$todos"},{$sort:{"todos.dueDate":-1}},])