MTL - Humans Are Falling Apart, Just In the Moon, Science God - Chapter 183

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.

Mediocrity is the normal state of most people, and some of them can’t even reach the normal state~ A young man from a small town, ugly and inferior, disliked by relatives and friends, mediocre grades…

All these changes started with a beam of light going to the university train, and the boy was bound to the high-quality male god system.

The days are getting more and more hopeful, and the system is really fragrant:

As long as you learn, you can modify your own bugs;

As long as you do good deeds, you can get corresponding banknote rewards;

As long as you are praised, you can get relevant talent blessings;

…

This, it’s hard not to love, okay!

- Description from novelbuddy

The vast Kunwu Mountains, one hundred and eight thousand. Spiritual ethereal sword rising, sweeping the summits of the nine provinces.

A modern day otaku is reborn in a wuxia world, becoming the little shishu of a little sect. Unexpectedly discovering he has the martial arts trade system of a garbage web game. Through it he can actually exchange for all of the martial arts in Mr. Jin Yong’s novels.

And so, Nine Yang Manual, Nine Yin Manual, Nine Swords of Dugu, Eighteen Dragon Subduing Palms… All kinds of amazing martial arts started to dominate the jianghu of another world…

- Description from Novelupdates

“You are boring and bland. Except for me, no one would want you.”On the eve of her engagement, the obedient girl Lin Zhiyi catches her fiancé cheating and is publicly humiliated.In a fit of rage, she chooses the most handsome escort.The man smirks, “I’m expensive, are you sure?”“No money, no man either.”Shredding her obedient facade, she takes full advantage of this man.She even brings him before her fiancé: “I can find someone ten thousand times better than you!”Her fiancé turns pale and respectfully calls out, “Aunt-in-law.”Lin Zhiyi: Huh?