Oukoku e Tsuzuku Michi - Chapter 512

Her family used her, her boyfriend cheated on her and had an affair with her stepsister, and in the end, she was killed by them. But fate took pity on her and gave her a second chance in life, and in this life, she promised to reclaim everything that was stolen from her by those scums.

But who would have thought that in this second life, she would also meet him? She was spoiled and pampered by him so much that nobody dares to bully her anymore.

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.

Senior high school student Dugu Hong was logical autistic and had a very high IQ. Despite his impressive IQ, he was never taken seriously by his teachers or schoolmates. While playing a recently released eastern Wuxia online game called Jiang Hu, three vicious classmates trapped Dugu into a mountain cave in the game with no hope of escape unless he deleted his account and re-register it. Not succumbing to their demands, Dugu decided to stay in the cave and explore the game system, which benefited him greatly. His persistence to obtain massive internal strength aided him in finding a superior way to improve himself, and thus opened the function of inner observation of the main and collateral channels. Meanwhile, in the real world, he discovered he had supernatural powers when he tried to save the girl he secretly loved who had caught the eye of a gangster on the suburban railway.

Asura – proud, warlike, cruel, heartless.

A young adult with a mysterious background follows his father’s prophecy and enters the world of «Rebirth», somehow managing to inherit the Xuanyuan Sword, and also unexpectedly obtaining the hidden class Asura.

Following the tracks of both virtual and reality he gradually discovers a secret hidden for the past billion years.

Asura, the class that used to shake the lands has now completely disappeared. He must now go on a journey to find the true meaning of Asura—until the day he transforms and becomes one with Asura.

- Description from Novelupdates