The Vampire & Her Witch - Chapter 661: On The Road (Part One)

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.

In the 21st century, she was the talented leader of the hidden family clan, once she crossed over, she became the number one waste?

Break off an engagement? A good-for-nothing? Open your ​​eyes and see clearly!

This lady here can just throw you into the skies and let you be closer to the sun.

With a red fan in hand to blow the world into a whirl of chaos, carving a name for herself under the skies.

- Description from Novelupdates

The heroine I was rooting for was not chosen.

Then wouldn’t it be okay if I made her happy instead?The heroine I was rooting for was not chosen.

Then wouldn’t it be okay if I made her happy instead?

In the age of the Warring States, the world is at war!

At this moment, a great empire is about to be established, and at this moment, this empire is at stake.

In this vast world, Young Master Qin shouted loudly, “I want this great Qin Wanshi–!”

- Description from novelbuddy