Interstellar: Return of the Villain - Chapter 21: Spicy Travel

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.

Wang Yi was reborn into a world that swallowed the starry sky. After eighteen years of ordinary and extraordinary, he finally met the conditions on the eve of graduation from high school, activated his own golden finger, and signed in for the first time.

[Ding, congratulations to the host for successfully signing in, signing in for the first time, and signing in to the earth, special rewards will be given to reward the first karma of the Nine Tribulations Secret Code! 】

[Your genetic level has increased three times! 】

“…”

- Description from novelbuddy

The world was destroyed, the apocalypse descended, a new era began, and the right to survive as a Lord was granted to every person.Domains, Heroes, Troops, Treasures, Resources—all of the countless servers constructed by the myriad continents were opened up.Qin Muye looked at his panel, which was akin to cannon fodder, and his domain with its damaged suffix, and felt a strong urge to cry but no tears would come.No divine talent, no hidden hints, no overpowered Profession.“If that's the case, then I'll just have to adapt and live in a different way.”

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.