Before you say that, maybe read the history of those treats first. Apfelstrudel is Austrian/Hungarian not even German. And Germknödel are likewise not common in Northen Germany but a Bavarian/Austrian dessert.
Northen German desserts are Rote Grütze, Windbeutel, Franzbrötchen and Pfannkuchen as well as fruitsoup with Klütchen. All those varying from region to region some being more prevalent in the East some in the west.
But you're definetly wrong on your take.
I'd wager bread and Bratwurst are the main pan-German dishes with minor differences in style