Return of the Legendary Runesmith - Chapter 55 - 54- The right answer

Branded as the last remnants of evil.Once known as Cero Restes, now living under the name Gabby Magus walked into villain’s path. He swore to hunt every hero’s affiliated with the Dukedom of South in the kingdom of La Magia.Through a web of lies, manipulation, and ruthless strategy, he will rise—not as a savior, but as the villain hidden within the hero’s party.

"I want to run away from everything."

The heavens and earth change when the blood phoenix descends.

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.