I'm a High School Boy and a Bestselling Light Novel Author, Strangled by My Female Junior and a Voice Actress - Volume 1, Chapter 2 - April 17, She asked me

Keeley, a simple plain Jane, hits the jackpot. [No, she did not win the lottery!] At least that's what she thinks when she marries the most eligible bachelor in New York City: Aaron, a wealthy cold-hearted heartthrob and Tycoon.

After the nth time of failing a marriage meeting, Xiang Han got himself a job: good treatment, high salary, free world traveling with food provided, house provided and even a ‘lover provided’?!

At first, he thought, apart from having to travel into the body of a scum cannon fodder, a scheming fake white lotus, everything else was okay. It was only later he realized that saving the target was also a problem. His imagination was neverending, even eating a cup of ramen was seen as a way to rouse his ( target’s) interest!

Xiang Han: This target is a no-go.

Certain Target: Very good, you’ve already managed to rouse my interest.

Xiang Han: Go outside and make a left turn to the optometrist, go get your eyes healed! Additionally, this “lover provided” isn’t necessary.

A Certain Target: This is certainly necessary!

- Description from novelupdates

In the 21st century, a female military doctor, Lu Jiao, transmigrated into a novel and became the vicious mother of four little villains and the wife of the future First Assistant.

In the novel, the four little ones would grow up into villains who committed all kinds of crimes and killed people without batting an eye. Eventually, they would end up getting killed by the male and female protagonists. To avenge his sons, the First Assistant would transform into the final boss and die after committing many sins.

Lu Jiao looked at the four little ones who were only up to her knees, then looked at the bedridden First Assistant. Forget it, she would do a good deed by educating these children properly and giving the First Assistant medical treatment while she was there.

What she didn’t expect was that the four little villains and the future First Assistant would want nothing more than to send her to her death.

They attempted to strangle her in the middle of the night, use broken pieces of porcelain to slice her arteries, and poison her food. Lu Jiao was furious. “I’m not doing this anymore. If you want to become villains, go ahead.”

However, the four little ones now refused to let her go.

“Mummy, please don’t go. We’ll be obedient from now on.”

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.