How To Survive as a Villain - Chapter 148: Learn More About The Flirtatious Jade Flute.

As a boss with space plant abilities in the apocalypse, Lu Yao once traveled to the future, became the director of a nursery school that was about to close down, and became a rare animal human on the verge of extinction.
The food she made at random can cure the genetic disease of the cubs in the welfare home. She punched the cubs’ scum fathers and scum mothers, and kicked the remarried families who abandoned the cubs.
It is such a good kindergarten successor dean, who is attracted by that single cool imperial marshal!
Since then, the barrage in the live broadcast room has become:
Imperial Citizen A: Dean A, I really want to marry.
A certain big black dragon: Shut up! This is your marshal’s wife!
CP: Dean Lu Yao, who is extremely protective of short-sightedness and loves cubs, X the imperial marshal Helanjia who loves Shang Yunxi more than cubs
Brief: There are no bad cubs, only bad big ones.

- Description from novelbuddy

The world’s largest scale virtual reality game, ‘Kailan’.

After ten thousand years of cultivation, he could have achieved immortality. However, his lack of human experience led to his failure to attain immortality.Thus, he resolved to immerse himself in a century of human existence, seeking to enhance his journey toward immortality. What he didn’t anticipate, though, was that upon entering the human world, he would find himself cast as a son-in-law, facing disdain not only from his wife’s parents but also from his beautiful wife herself.Armed with a wealth of cultivation knowledge, how could he transform his drab human life?

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.