I Became the Demon Lord and my Territory is an Uninhabited Island - Chapter 79.1

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 playing a variation of the poker game, Shadow’s Hand, Damien Pearce unexpectedly awakened in an unfamiliar world.Stripped of all kinds of information in the world he was thrown into, Damien now had to navigate it through wits and guts.Amidst his search for information, he discovered that he seemed to be a part of the world as a Transcendent Investigator, otherwise known as TI.The TI seemed fearful and revered among the people in this world. They were responsible for catching Transcendent(s) who misused their power.But was that the reason for his transfer?“Do I or do I not belong in this world?” Damien questioned his presence constantly.

Lu Wu, an aimless video game developer, had been feeling perturbed ever since he found out he was the direct descendant of a king from the underworld. Other than the title, His Excellency, his ancestor hadn’t passed down anything else to him. On top of that, all of his ancestor’s subordinates had rebelled against him and completely usurped his inherited territory.

In short, MC inadvertently created a world, but as the creator of the world, he did not know the world at all. He should have lived here like a fish in the sea with some plug-ins that MCs always have. But now he is even stumped by the bugs in the instant world. Luckily, in this world he has found his shadow guard, or his lover? So the daily adventure is getting not so boring…

- Description from Novelupdates