Getting a Technology System in Modern Day - Chapter 14: Payment invoice

Wu Lai was an ordinary high school student. One day he was struck by a flash of lightning from a different world, and suddenly entered a fantastic world full of magic and swords. Since then, he started a totally new life. In this supernatural world, he had his ups and downs, experienced numerous battles, subdued powerful evil beasts, and fell in love with a belle. His nickname “Demon King” was remembered throughout the ages there.

Stay or return was a question. In the face of this choice, Wu Lai, with the nostalgia and gratefulness for the original world, finally chose to stay…

Here was the legend of “Demon King”…

- Description from Novelupdates

Shen Yubai from the international class is a wealthy young master, enormously powerful and notoriously difficult to deal with, haughty and proud. The transfer student, Shen Sinian, is fresh and handsome, sunny and cheerful, with a mysterious background, almost mythical.Xu Chuning from the regular class and her mother rely on each other, living a meager life, attending school with the aid of scholarships. She should have nothing to do with either Shen Yubai or Shen Sinian.However, recently, schoolmates have noticed that she and the transfer student Shen Sinian are unusually close, their interaction ambiguous. Shen Sinian seems to do everything she says, whereas Shen Yubai from the international class shows special attentiveness towards her.One day, schoolmates even overheard Shen Yubai cornering Xu Chuning, asking her in a deep voice, “Who is better, me or Shen Sinian?”Classmates: “?”Is this some kind of love triangle showdown?

I cut from south to north,

I cut from white to black,

I will cut down the thousand mountains and the ten thousand waters,

I want the world to know who I am!

I am Gu Zhan,

Gu Zhan who wants the whole world to surrender!

- Description from novelbuddy

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.