The end of the war was already described in this manga, though ... The war ended when Not-UK sacrificed it's whole navy to distract the Devil of the Rhine from a landing in not-Germany and then not-Germany acepted to come to the negotiation table. After that, there was a economical crisis and a lot of chaos in not-Germany ( that is how the lack of intel on Tanya is explained ).
Now, while that looks like a defeat for not-Germany, it is clear that not-Germany was not occupied and, given what we know about the not-Germany war objectives ( they were not trying to conquer anyone and were mostly trying to stop a increasing ammount of attacks on them on all fronts ), maybe not-Germany only got what they wanted: to stop the war and force their enemies to the negotiating table. Maybe if we actually heard some not-Germany diplomats from the time instead of not-UK reporters with a very thin acess to real facts on the subject, we would have the oppossite impression that not-Germany had won the war and that the economical chaos that came after was a unfortunate consequence of the titanic war effort they had to do to not lose it ...