I've always sort of thought of the Third Reich as an attempt to rebuild the Holy Roman Empire plus the Prussian territories. The First and Second Reichs kind of combined I guess. The conquests like Poland and Ukraine I always figured were planned to be administered more along the lines of colonies or with military governments for an undetermined amount of time. It's interesting they considered the Dutch as Germans since they had not even been formally part of the HRE since Westphalia and really split off much earlier than that. Makes me wonder what they planned for the Scandinavians.