The Real Young Miss's Secret Identities Revealed - Chapter 18

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.

Dark purple skies and deathly black clouds herald the arrival of the apocalypse. The earth shudders and groans as the Dark Matter wave mutates the very planet itself, and those within it.Follow Henrick as he fights for the right to survive, and navigates this treacherous new world.

Violet skies, a world undergoing massive changes, a deficient moon, interlinking voids…
When the world experienced a cataclysmic event,the majority of living things ceased to exist. Although humanity survived by hiding in the last safe zones, humans had to face mutated dire beasts and colossal source beasts that could break through the space barrier and enter the earth at any second.
Luo Yunyang, a young man who grew up in those calamitous times, obtained an attribute regulator and set out to walk the path of supremacy!

- Description from novelupdates

“The missing ingredient is a test subject with Royal Blood...”Raven Kyzer, a Commoner boy, grew up in an orphanage along with his twin sister, after losing their mother at a young age, having never met their father.After being discovered to possess Royal blood, the twins are abducted by the Church of Persona. Raven is used as a test subject in an ancient form of Forbidden Magic, known as the Homunculus Ritual, while his sister goes missing in the clutches of the church.The Homunculus Ritual is conducted to turn Raven into a powerful but mindless Monster, a loyal weapon for the church with no sense of free will...but something goes wrong, the ritual fails to destroy Raven's mind and he escapes the clutches of the church.Furious at being turned into a Monster, Raven swears revenge against the church, determined to make them pay for what they did to him, as well as to rescue his sister from their clutches.But there's only so much he can do by himself, even with the new powers he gained through the Homunculus Ritual...that's when he has a fateful encounter with the nation's most wanted criminals, a group known as The Irregulars, who, like Raven, have their own reasons to despise and go after the church, as well as the corrupt Nobility that oppresses the Commoners.With their goals aligned, Raven decides to join The Irregulars, taking the first step on his long, arduous path to revenge...