Amelia the Level Zero Hero - Chapter 230

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

A useless prince, yet brimming with kindness and compassion—his smile as warm as sunlight, illuminating this darkened era.But that was merely a mask, hiding the poisonous and mad nature beneath.A monster lurking behind a gentle shell.A system that feeds on stolen Heroines.He will outplay destiny—and rise as the world’s ultimate villain.

Wang Xiao was compelled to descend from the mountain by his master, with his intrinsic energy cloistered, and a lovely woman erroneously believing him to be her betrothed. In a bid to safeguard his mistakenly assigned fiancée, he resolved to remain in the school teeming with enchanting beauties. With the same intent to defend his intended, he managed to transform the currents of power within the city.

Three years ago, Yun Qing Yan fell into the Immortal Realm from the mortal realm. Three thousand years later, he became Divine Emperor Yun who shook the entire Immoral Realm. Breaking through the void and returning back to the mortal realm, Yun Qing Yan discovered that only three years’ time had passed here. “In the past, I did not possess the power to protect the people I hold dear. Now, I want the entire world to grovel at my feet.”

- Description from Novelupdates