Germany was created after the french-prussian war during the XIX century
It existed long before that as an ideal among the majority of the inhabitants, there is a reason why its full name is called Holy Roman Empire of German Nation. The Emperors were always also German Kings, and particulary the Austrians always called themselves Germans. One of the reasons why Martin Luther was so succesful is because the people in Germany wanted to be free from the perceived "Italian" Papal opression and the German princes could claim to defend "German liberty".
northern Italy, Benelux, southern Denmark and Pomerania
The Bohemian elites were predominantly German-speaking, Slesvig-Holstein and Pommerania *the parts that belonged to the HRE) were after the middle ages thoroughly German as well. Not every region was German of course, but the core certainly was, so of course the HRE is a predecessor of Germany. Or would you argue that since Poland had before 1945 territories that were not predominantly Polish, it did not qualify as Poland?
centralization of the most eastern part of the inheritance of Karolingian Empire
In short, what became Germany.