MTL - The Rumored Second Son - Chapter 165 Episode twenty-ninth

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.

She, the “godly doctor” of an assassin organization in 21st century, transmigrated into the body of Yun Family’s abandoned, good-for-nothing Ninth Miss. Good-for-nothing? Then she’ll let the world see what a real good-for-nothing looks like. Summoners are legendary? Nothing is impossible in this world! She’ll become the first Magical Summoner.

There was a special patient in Spruce Hospital. A person in vegetative state and coma that the tree doctor, So Lee-yeon, has been hiding for two years…‘Don’t wake up. Please don’t wake up.’It was her dream to live quietly so she prayed every night. Then one day, by pure miracle or failure, the person in vegetative state woke up!“Did you come to suck this poor bastard’s dick?”In front of the man that lost his memory and common sense, she told a lie that couldn’t be turned as she was afraid of his mu*derous instinct.“I’m your w-wife, Kwon Chae-woo.”To the man who buried someone alive and tried to kill her two years ago!