MTL - Group Pet Little Fat Baby: I Have Four Big Daddies - Chapter 214 give you an explanation

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.

It was the best cheat in the vast and ancient world!Its origin could be traced back to Trailokya and it was the highest law!…Three years ago, three living creatures fell from the sky. King Monroe of West Ridge got one of them and he conquered six countries to unite West Ridge.Wu Zhao of the Big Zhou Dynasty in the Southern Wasteland got another one of the living creatures. She dominated all 19 clans there and became the top figure in that region.Owen Bertram also got one of the living creatures. Yet three years had passed and he was still a nobody. Nothing had changed for him.However, he soon realized that the tiny loach that he got three years ago was actually the biggest cheat in the world.Moreover, it led him on a non-stop journey of becoming the biggest winner in life!

She had a lifetime of fake virtue without receiving a virtuous ending. In the next lifetime, she controls fates with the flip of her hand. To the jerk who wasn’t faithful, she’ll draw a premature death talisman for him. For the poisonous step mother, she’ll send a death flower. For the step sister who is two faced, she’ll personally rip off that fake pretty face!

But when she personally offered up her body to her nemesis because of a child who she had no fate with, something unexpected happened. The night of the big wedding, the groom changed and a cold and luxurious man pushed her down. “You can marry whoever you like, but you can only give birth to my children!”

- Description from Novelupdates

I had thought that my life couldn’t get worse when I walked in on my fiancé cheating on me with my best friend. But after a series of unfortunate events, I opened my eyes in a world that I had only read about in a webnovel, the Erudian Empire, ruled under the domineering, bloody reign of Emperor Helio.

The worst part?

I’m not even the main character! Reborn as Winter Royberg de la Erudian, I am the pitiful side character who is discovered to be a royal bastard princess due to a certain physical trait only the imperial bloodline possesses. But I know the end of Winter’s story and the unwanted royal punching bag is framed as a witch and killed at age 16 on the guillotine due to the scheming of the cruel empress.

An aloof, murder happy father? Check.

Psycho half-sister? Check.

Meddlesome author who wants me to follow the script? Double check!

I don’t want to die an early death again, so I’m determined not to ever be discovered as a royal again. But before I know it, I’m trapped in a palace of blood and opulence playing tricky games of power, games I have no clue how to win. How will I survive to adulthood in the imperial palace and get my happily ever after? And am I really the only person who fell into this world?