Later, He Became A Royal Healer - Chapter 34 - It's impossible to sleep.

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.

"Your bed is cold," spoke a voice in the room that had her eyes go wide in fear. Nervously, she turned around, gulping softly to see a shadow on her bed as if someone laid down there. The man who had been lying down sat up emerging out from the shadows where he had been waiting for her.

Lin Xun unintentionally downloads a text game called “Book of Salvation”.Leveling up and taking adventures is just standard procedure.Not only can he bring game items into reality, but he discovers that he can also bring game characters into the real world…Although the game difficulty is hellish, luckily, Lin Xun has an unusual talent.While other Apostles can only use one game character…Lin Xun is hesitating over which one of the game characters he should use.While other Apostles are still using weak human characters...Lin Xun is already using powerful monster BOSS characters.…Then one day, when Lin Xun brings a terrifying BOSS into the real world...“Would you believe me if I said I'm here to save the world?”

Shocking big news: Gu Qingning, the good-for-nothing daughter of the Gu family, is no longer dumb, and her IQ is on the line.

Hearing that Gu Qingning got perfect marks in the grade-jump exam, everyone sneered, “It must be cheating.”

Sister Ning was not angry, and rejected the olive branches offered by other top universities, and took the recommendation of University A to sit firmly on the throne of the god of learning.

Hearing that Gu Qingning wanted to build power, everyone laughed again, “Waste wood can build power, and men can have children.”

Sister Ning didn’t get annoyed, she started her career silently, made a fortune silently, and abused scum while wearing a vest.

Hearing that Gu Qingning is in a relationship, everyone laughed again, “What kind of blind man would fall in love with her devil.”

On the same day, the most mysterious prince in the Beijing circle posted an official announcement on Weibo.

——Mrs. Fu, what do you want to eat tonight? @Gu Qingning

The whole city boiled, and it turned out that they were the ones who were blind.

From then on, Master Fu and Sister Ning joined forces and never looked back on the road of slaughtering dogs.

…

“Master, madam beat up the heir of the Rawls family.”

Fu Juncheng, “Send a few more people to help beat her up, don’t tire her out.”

“Master, madam is robbing us for business again.”

Fu Juncheng, “Who asked you to rob her, and send her the plan.”

“Master, your mother said that Madam seems to be pregnant.”

“boom–”

There was a sound of slamming the door, and the tall and straight figure of the man had long since disappeared.