Cinnamon Bun - Chapter Two Hundred and Fifty-Seven - Quarry

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.

What if you could hack the strongest heroes and turn them into your devoted companions?Once feared as the Heavenly Demon, Zain stood above all—unstoppable, unrivaled, unchallenged.But his reign came to an end when so-called righteous cultivators banded together to eliminate him, believing they had purged the world of its greatest evil.Yet death was not the end.Reborn in a world dominated by heroes and champions of justice, Zain awakens a mysterious Hero Hack System—a power that doesn’t just defeat heroes but rewrites them.With a single command, he can shatter their convictions, twist their destinies, and rebuild them into something new.A ruthless warrior queen? Now a loyal blade at his side.An untouchable holy maiden? Now eager to obey.The strongest hero who once stood against him? Now kneeling before him, waiting for his command.With every hero he hacks, his harem of once-unshakable warriors grows. But as he reshapes this world to his will, one question remains—who gave him this system, and what price will he have to pay?They ended his reign once. This time, he’ll reign over them all.

Athena Grant,a human,dies in a car accident and becomes Eira Liora,an elf. Transported to the barren and cursed island of Luinmir, a once-thriving land now abandoned.A year ago,their King announced that the island,Luinmir would no longer be under the empire's control. It was well known that the land was barren and poverty stricken...She was abandoned both by her Kingdom and her Father.She wakes up one day with a system.“So what if they were abandoned and deemed cursed,she would show them all the highest peak of knowledge and development. The island's core is broken...fine,she'll get it replaced but this time,the island would become hers to keep,she would make sure of that.”

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