Hearts of Iron: the Return of the Kaiser

Single female protagonist (the female protagonist does not have a vase) + intrigue + struggle for hegemony + farming? William starts a debate with an art student. So a concept that originated from red, transformed into black, and finally became golden was born. But Berlin was still in turmoil, the Wei government was incompetent, and the economic crisis was approaching like the end of the world. William, the heir to the Hohenzollern family (a character who does not exist in this world), awakened to the "Hearts of Iron 4" system from the future at this moment! The torrent of steel, the craze of science and technology, political games, intelligence infiltration... He used the system, from industry to military, from internal affairs to diplomacy, step by step, to regain the power of Calder in the midst of the great powers, and establish the Great Calder Empire! Various black technologies have also emerged... Land cruiser, space carrier, UFO... This is not only the rise of an empire, but also an epic about a man who shoulders the destiny of the nation and mankind. Side by side with him is the Bavarian Edelweiss who went from being conservative to being firm... Note: This story takes place on a planet called Blue Star and has nothing to do with real history or characters. Any similarity is purely coincidental.