In the 21St Century, an Engineering Man Leads a Princess to Conquer the World by Lowering Her Dimensions.

I, Qin Xiao, the top engineering master of the 21st century, wake up and become a useless prince who can be bullied by everyone? My predecessor was cowardly and incompetent, leaving a mess. The palace was extremely poor, and the princess looked at me like she was trash. Okay, I'll take this script! Making soap, running assembly lines, training new troops... You fight for power and profit, while I quietly make a fortune. I wanted to be a free and easy millionaire, but there were always people forcing me to take action. When my modern technology reduced dimensionality and hit this era, when my invincible fleet lay across the coast of the enemy country, the whole world discovered in horror: This King Xiaoyao, who had been ridiculed by them for half his life, had already trampled the world under his feet.