[{"_id":ObjectId("57315ba4846dd82425ca2408"),"aggregates":[{date:"2022-01-30",x:1},{date:"2022-02-03",x:2}]}]

db.collection.update({},[{$set:{aggregates:{$cond:[{$in:["2022-02-02","$aggregates.date"]},"$aggregates",{$concatArrays:["$aggregates",[{date:"2022-02-02"}]]}]}}}])