db={products:[{"_id":ObjectId("5f36c0df6d5553e6af208cac"),"items":[{"paramType":"Meeting","paramValue":"5f36c0df6d5553e6af208cab"}],"ownerId":ObjectId("5f36c0df6d5553e6af208cad")}],meetings:[{"_id":ObjectId("5f36c0df6d5553e6af208cab"),"startDate":ISODate("2020-08-18T00:00:00.000Z"),"endDate":ISODate("2020-08-18T00:00:00.000Z")}]}

db.products.aggregate([{$match:{"ownerId":ObjectId("5f36c0df6d5553e6af208cad")}},{$unwind:"$items"},{$lookup:{from:"meetings",let:{"meetingId":{$toObjectId:"$items.paramValue"}},pipeline:[{$match:{$expr:{$and:[{$eq:["$_id","$$meetingId"]},{"$gte":["$startDate",ISODate("2020-08-01T00:00:00.000Z")]},{"$lte":["$endDate",ISODate("2020-08-31T23:59:59.999Z")]}],},},},],as:"meeting"}},{$unwind:{path:"$meeting"}},{$project:{"_id":1,"items":1,"meeting":"$meeting"}},{$sort:{"meeting.startDate":1}}])