MTL - Sword Among Us - Chapter 1264 Soldiers under the city (recommended)

Reborn in a parallel world, this place is imbued with eeriness everywhere... Do not enter the bathroom after midnight. At two in the morning, the sound of knocking resonates on time. A woman, haggard and emaciated, always stands with her back to oneself. Encountered a strange event? Lucky for me, I can Rewind! This is the story of a Reincarnator, carefully navigating a reality invaded by the bizarre, combating the strange with bizarre poses.

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.