I Am a Salted Fish in Ancient Times - Chapter 56: A Delicate Situation

At 3 years of age, her father went missing. At 15, the muscle in her hand snapped. At 16, her mother passed away in a car accident. At 19, she was framed by her uncle. At 22, she was burned alive by her newly- wedded husband and her best friend. Perhaps it was God’s sympathy that allowed her to return to the time when she was 15 years old to re-live once more. The previous lifetime of being low- key and having forbearance resulted in betrayal and misery. In this lifetime, she must be lofty and domineering to let those who have bullied her suffer a terrible end!

- Description from Novelupdates

The Super Soldier in the City, the invincible champion who strides across the urban landscape, wanders through day and night.

Ryu Han-bin, the main character who fell into a new world after being chosen as a ‘suitable person’.

Because of the error in the guidelines, the training is repeated endlessly…

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.