Miss Shen is Actually A Bigshot in Witchcraft - Chapter 69 - : Second Young Master Fu Is Jealous

Civilization is destroyed and records lost. Only Dudian survives in a cryogenic sleep. Three hundred years later, Dudian wakes up and must become Dean to survive. Who can he trust in this world overrun by monsters without and within?

Sato Yu is a 12-year-old boy. He is a deprived person. His life is depriving. His step father has a large amount of debt.

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.

Weiss is an ordinary young man caught in the changing times who is studying magic from an unknown natural event. When he feels weak and helpless in facing a world that is constantly changing and filled with magic, he awakens his secret ability, the “Maid Order”. Special abilities that make him a “Master” who will be respected by the “Maids” who are loyal to him.