Citadel for All: The Only Unit Angel at the Start of the Game - Chapter 491

For three years, Finn Taylor is utterly humiliated. He has endured everything from physical beatings to verbal abuse. For three long years, he has gone by only one identity—the useless matrilocal son-in-law of the Larson family. But this life as he knows it is about to be turned upside-down as he reclaims his position as the head of Peregrine Hall.

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.

After a seven-day slumber, Chen Yun discovers that his body is undergoing inexplicable metamorphoses that cannot be explained by science.Evolving flesh, unimaginable abilities, mystical secrets...All his previous pursuits now seem trivial, including money and career.The existence of a mythical realm in fantasy also doesn't seem too far off.

Great Cultivator Chen Fan had failed his Tribulation period, but after a dream, he had returned to Earth, when he was young, five hundred years ago.