My Simulated Road to Immortality - Chapter 1684 - 1397: Xuan Huang Ascends to the Immortal Domain_2

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.

I reincarnated as a lizard in a martial arts world.“Roar!”“He’s using the lion’s roar!”“To deflect the Ten-Star Power Plum Blossom Sword Technique! Truly indestructible as they say!”“This is… the Heavenly Demon Overlord Technique! It’s a Heavenly Demon, the Heavenly Demon has appeared!”It seems they’re mistaking me for something else.

In the past, the giants of the heavens and the gods were destroyed after the reincarnation of the world! Cruel curse, eternal hatred, Tan Yun is determined to never sink again! For the sake of loved ones and relatives, from now on, step on the corpse of the enemy step by step to surpass the peak! Defying the sky, killing all worlds, I am the only one!

- Description from novelbuddy

Humanity achieved dominion over the galaxy long ago.Once that was accomplished, they turned their ingenuity inwards. With their prowess over biological engineering, they transformed themselves into deific beings now called the Gene Tyrants. For centuries, the Gene Tyrants terrorized the galaxy, designing and abusing their genetically engineered servants and serfs as their whims took them.No tyranny can last forever, though, and the Gene Tyrants were eventually overthrown. The rebels discovered a strange light of the mind called Aether, which gave them the strange and fantastical powers they needed to eradicate their creators. Once that was done, however, that by no means meant peace.In the thousand years since, the face of the galaxy has changed. The most powerful human civilization is called the Supremacy, the homeland of 'might makes right'. In the Supremacy, a crime committed by the strong is no crime at all. With their military strength and mastery of Aether, the Supremacy has spread across the galaxy -- with the other powers able to do little but stall their advance. This struggle has developed into a cold war, and that cold war has frozen over for years now.Dragan Hadrien, a low-level administrator in the Supremacy, cares nothing for any of this. Dragan's primary concern is getting himself a promotion and taking it easy for the rest of his days. When a mysterious prisoner is brought aboard his ship, he thinks he has found the means to do just that.How naive of him.