Dungeon Diver: Stealing A Monster's Power - Chapter 27

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.

“Alas, this life is a failure; let’s see what the next life holds.” ... “The second life has ended, calculating results... Final rating: C+. Rewards based on rating: You may choose to inherit one item from Constitution, Skill, or Talent. Please select?” “Hmm, I choose to inherit the Talent ’Dynamic Vision’.” “Talent inherited... Congratulations on achieving the following lifetime achievements: Innate Grandmaster; Blessing of Many Offspring (10/10)” Achievement rewards: Two random rewards. You may draw from Constitution, Skill, or Talent, or choose to upgrade Talent level. Please select? ... A reborn individual, in possession of the treasure ’Hundred Lifetimes book’, reincarnates within the Cultivation World, undergoing endless cycles of rebirth without the bloodline ending or the soul perishing! The family he established ten thousand years ago has now grown into a massive entity that spans the heavens. The disciple taken in casually eight thousand years ago ultimately became the founder of a Great Sect in the Immortal Realm. The pet raised three thousand years ago has evolved into an unparalleled Demon Saint of the Otherworld. ... I am Zhao Sheng, and I shall cultivate life after life until Ascension!

This stands at the forefront of strategy guides to Life (a shitty video game)!

Cosplayer Liu Mang accidentally crosses through time and arrived at the Eastern Han Dynasty wearing Aries Gold Cloth. (Saint Seiya!) He arrived on top of the walls of XiaPi right when it was about to fall to Cao Cao.

“Don’t kill me bro; I’m not working for boss Cao!”

“Hey! You’re slashing the wrong person! Boss Lu’s underlings are there! Not me!”

He accidentally saved Lu Bu who was tied up by Song Xian. He accidentally became the son in law of Lu Bu. He accidentally changed the history of the Three Kingdoms period.

When aluminum casted Gold Cloths are worn by generals like Zhang Liao and Gao Shun during the Eastern Han Dynasty, glistering on their bodies… When the soldiers in the camps are sporting mechanical crossbows… When crossbreeding of rice plants appeared on Lu Bu’s territory…

Liu Mang knows that a world belonging to Lu is coming.

- Description from Novelupdates