I created Magic! - Chapter 88 Elric Arrives!

Tsubasa gets a second chance, reincarnated in the Naruto world.However, fate throws him into the Sengoku era, a time of relentless conflict.His sole advantage? A one-time cheat to create a ninjutsu. 'Venom' is his creation, his hope.Can this single ninjutsu ensure his survival and perhaps, something more, in this savage age?

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.

After dying, Chen Heng finds that he has transmigrated to an alternate reality: everything is the same, except the world is now a Wuxia world heavily influenced by martial arts! Not only this, he discovers that he has a Fantasy Simulator, from which he obtains rewards that make him incredibly powerful in his new reality as well. Martial arts, immortal cultivation, and overpowered abilities–all of this begins from a single simulation!

Qiao Xia, as TVE’s new entertainment reporter, had a good timing. She accidentally filmed her female cousin and her own fiancee’s scandal. And after one misfortune, a second misfortune got added ! When fighting helplessly alone, Qiao Xia, the pure and innocent little white rabbit, suddenly met the charming and arrogant male god – TVE’s crown prince Mu Liang.

Male God: Marry me.

Male God: I have a house, a car, a good looks, and also an unparalleled IQ. Where will you find such a good man?

Male god: My IQ is 130. Marry me, and you will never be defeated !

Qiao Xia: …So I’m afraid that means you’re not a fool ?

But when she fell in love with the male god and wanted to spend the rest of her life with him, the male god retracted…

Anrgy Qiao Xia : What kind of male god are you, you simply are a scumbag!

Male God: Alright, since you want to get married, I will be a bit unfair to you and marry you.

What Qiao Xia didn’t know was that the male god had kept her in his heart for more than ten years.

“I am your cloud, on which you can stand for the rest of your life, with which do whatever you want, on which you can watch the world’s scenery. Even if you fall, it will fall on me. I will stay with you even in danger.”

- Description from Novelupdates