I Was a Sword When I Reincarnated (WN) - Chapter 16: Arrival at the Town of Aressa

Suo Fei, a veteran NEET has spent three-days and three nights strategizing his way through the highly explicit H danmei game masterpiece “Yalance”. Furthermore, he was able to capture all nine little shous from the nine great races. However, as the final, 10P feast was approaching, he unexpectedly transmigrated. He transmigrated into the real country of Yalance…

Suo Fei: Hey, hey, hey, can you delete these files and let me restart? What the hell did Laozi transmigrate into!

- Description from Novelupdates

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.

The legendary mercenary Great Emperor, the “Forbidden God King” Ye Chenfeng, had returned to the city, sweeping away everything with an invincible stance.He had unveiled millennia-old mysteries, Atlantis, the Maya civilization, and the astonishing secrets hidden beneath the Himalayas...

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.