πI recommend the following novels to you: 1. "God-level Main God Civilization System": The male protagonist was summoned by the Main God Civilization System to return to Earth in 2005. He brought the futuristic system to control the storage, combat, and money-making systems, starting a new life. It can satisfy your needs for future technology, systems, and cities, but only one wife. 2. "I Inherited the Alien System": After the male protagonist accidentally discovered an alien system hidden in an alien spaceship, he returned to the city and laid his cards on the table, leading Earth to the interstellar space. End, no harem. 3. "Livestream: Review Mark I Armor at the beginning of the game": The male protagonist will promote and review future technological creations through livestreams, bringing future technology to everyone. It can satisfy your needs for technology, super technology, and light novels. End, no harem. I hope you like this fairy's recommendation. Muah~π