My Succubus System - Chapter 208:

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.

Among the demons, the supreme ones are called “Great Saints.”

A young man leaves his mountain village and travels around the world. By unceasing efforts, he finally becomes a legend of the age.

- Description from Novelupdates

This story tells the life of two people, a noble only in name and an older wife from the army, married through a tentative agreement. In the bone-chilling cold, they spend their time hunting, gutting, and cooking by the fireplace. Their daily life passes peacefully. This is the warm love story recounting their daily lives.

In the last life, Lan Muyu ran away from home for love, but accidentally bumped into her object – the adultery of the popular actress Fu Yao. In order to keep her reputation, Fu Yao and Xiao San teamed up to drug her, and she jumped down from the thirty-ninth floor so that she would not be humiliated.
Her career was ruined, and all the betrayals left her to recognize her, but after her death, her fiancee Li Ruonan tried her best to avenge her, and she was implicated in her death.​​
Once again, facing the cheating scumbag girl, Lan Muyu, who had learned from her previous life, smiled coldly. She quietly took a video and turned around and ran away. It was uncertain who would win this time.
Looking at the pouring rain, she knocked on the door of the luxury car that had just stopped, “Miss, look at me… hey!”
Before she could finish speaking, she was stuffed into the car – what kind of person was she, Li Ruonan, the fiancée she abandoned for love!
Until Fu Yao and Xiaosan’s resources were cut off, and the company’s investment became a bubble, only to find that Lan Muyu was already in the high starlight, holding the hand of the chaebol heir and smiling in all manners.
​​
Li Ruonan (attack) VS Lan Muyu (shou) cover is Shou!
Note: Gongshou 1v1 Shuangjie, the Lord of the Year has no children

Content tags: rebirth sweet text cool text revenge abuse scum
Search keywords: Protagonist: Lan Muyu; Li Ruonan ┃ Supporting role: Please pre-receive “I became the villain’s favorite after wearing the book” ┃ Others: rebirth; attack change; scumbag
One sentence introduction: However, he was taken home by his fiancée
Purpose: face danger, live optimistically

- Description from novelbuddy