The Man Picked up by the Gods - Volume 5 - Chapter 28

Cao Xin, a young man on earth, died in a car accident, traveled to a troubled world where supplies were scarce, and obtained a “Bronze Immortal Gate”…

…

- Description from novelbuddy

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.

One day he suddenly found himself in hell.
All he had was the desire to live and a predation ability.
From the first to the ninth thousand circles of hell, he absorbed dozens, hundreds of thousands of demons.
Even the seven great dukes of hell bowed down before him.

– Why would you wish to go back? Doesn’t his highness have everything that’s in Hell?
– What do I have?

Nothing to eat, nothing to enjoy!
The only things in Hell are the barren lands and terrible demons!

“I’m going back.”

After ten thousand years he returns to Earth.

The Spirit Blade Sect was founded in the year 4233. After thousands of years of producing first rate Xiuxian geniuses, it had become one of the five biggest sects in the Ten Thousand Celestial Alliance. The head elder, Immortal Feng Yin is one of the seven Executive Elders of the Ten Thousand Celestial Alliance, with a cultivation that can shake the whole world. The Spirit Blade Sect is dedicated to peaceful development, and holds the core values of Truthfulness, Kindness and Loyalty. In order to expand the sect and bring in new blood, all heroes and geniuses have been welcomed to attend the Celestial Gathering.