The Hated Hero: Sigil-Powered Warrior - Chapter 11: The Missing

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.

Mimizuku, a small girl with chains on her wrists and ankles and the numbers “332” branded onto her forehead, wanders into the Forest of Night seeking to be eaten by a monster. However, when the ruler of the monsters, the mysterious and beautiful “King of Night,” refuses to eat her, she tries to formulate a way to convince him otherwise.

Ethan transmigrated from earth to a post apocalyptic martial world with a system.His system has only one function: Double the attribute every day. Watch him rising in the universe with a pace faster than the speed of light.

She was originally a daughter of a thousand gold, but who would have thought that her father would be demoted to the south of the Five Ridges once. Start with a dilapidated house, nothing you want!

A broken house is a broken house. A family working together is better than anything else. Zhao Liya took her parents, brother, sister and righteous brother to open up wasteland and farm, and make a fortune. There are treasures everywhere in Lingnan. If you work hard to start a business, your life will become more and more prosperous.

In the process of working hard to farm and make money, she met a very compatible partner. She pointed east, and her partner would never go west. She said that she would go to the sea, but her partner would never go up the mountain. Making spices, opening a restaurant… My partner said: “Good!”

Zhao Liya is very satisfied, give her another fight with such a partner!

Partner: “Not good! Just me is enough!”

Later, when the partner’s identity was exposed, Zhao Liya clenched her fists, “It’s really enough to have you alone!”

- Description from novelbuddy