Arifureta Shokugyou de Sekai Saikyou (WN) - Volume 2 Chapter 1

He had crossed into the dark, ruthless Wizard World.Lucien found his system somewhat different from the usual golden finger.System upgrade points? Chip activation?None of these, but rather becoming a role model, transforming into a nurturing breeze:Teaching students knowledge, receiving advanced knowledge in return.Caring for and maintaining students, earning generous rewards.[Your student has mastered the Magic Potion “Kuru's Cough,” congratulations on acquiring the improved formula “Kuru's Cough - Enhanced”!][Your student has mastered witchcraft “Fireball,” congratulations on learning witchcraft “Greater Fireball”!][Your student has successfully crafted the wizard's tool “Pale Mask,” congratulations on acquiring the wizard tool’s manual “Revised Pale Mask”!]Initially, Lucien was resistant.But after experiencing what it was like to teach disciples and outdo them, Lucien felt he had completely transformed into the form of the master system.This thing, isn't it much more useful than something called Cheating Device?

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.

The World Tower has unimaginable wealth and treasures. Once a week, as long as you rush high enough, you can surpass ordinary people and enjoy a brilliant and glorious life.

A thousand floors are capped, and some people say that reaching the thousand floors can get the wealth of the whole world; some people say that above the thousand floors is a beautiful new world or even heaven; some people say that they can obtain the power of gods;

Unfortunately, no one has reached the summit for thousands of years.

The strongest team in the world rushed to the 929th floor, which was unprecedented, and was still destroyed.

Wang Wen survived.

Time went back to twenty years ago.

Reborn with all the emotions and experiences, the lush Wang Wen in front of the World Tower is calm and determined.

- Description from novelbuddy

One moment, Lucas closed his eyes to sleep. The next, he opened them to find himself not in his bedroom, but in a courtroom.Even more startling, he was in a different body.Lucas was confused, but there was no time to dwell on it.Why?Because....“Your Honour, please sentence him to death!”the prosecutor demanded, looking directly at Lucas, who was seated on the judge's bench.'It seems I have become a judge.' Lucas realized.