[{"_id":"608642db80a36336946620aa","title":"titleHere","types":{"exampleOne":[{"_id":"6086430080a36336946620ab","front":"front","back":"back"},{"_id":"608a5b186ee1598ac9c222b4","front":"front2","back":"back2"}],"exampleTwo":[{"_id":"608a5b290e635ece6828141e",/** the queried document*/"normal":{"front":"2front","back":"2back"},"reversed":{"front":"2frontReversed","back":"2backReversed"}},{"_id":"608a5b31a3f9806de2537269","normal":{"front":"2front2","back":"2back2"},"reversed":{"front":"2frontReversed2","back":"2backReversed2"}}]}}]

db.collection.aggregate([{$match:{/** filter the document so uniwnd and group have only 1 record to deal with*/$or:[{"types.exampleOne._id":"608a5b290e635ece6828141e"},{"types.exampleTwo._id":"608a5b290e635ece6828141e"}]}},{$group:{_id:"$_id",docs:{$first:{"$concatArrays":["$types.exampleOne","$types.exampleTwo"]}}/** join both array into 1 element*/}},{$unwind:"$docs"},/** break into individual documents*/{/** filter the records*/$match:{"docs._id":"608a5b290e635ece6828141e"}},{$replaceRoot:{"newRoot":"$docs"}}/** set it to root*/])