Lady Lin’s First-ever Journey to Immortality - Chapter 414 - One Hundred Years of Solitude

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.

Zhou Yu, a reclusive otaku, who did not like to go out of his house, was one day forced out of his house by a series of unexpected events.

- Description from Novelupdates

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?

- Description from Novelupdates

“Go Yohan, you really are a terrible bastard.”“I can’t help it. Bullying is more fun than being bullied.”Despite his outer appearance of a kind model student, Kang Jun was filled to the brim with an inferiority complex.As he advanced into his second year, he grew closer to Go Yohan, who was in the same class as him.“I’ll treat you especially different.”At some point, as if it were only natural, Go Yohan claimed his seat at the very summit of the pyramid inside the school.He, whose second nature seemed to be ignoring and suppressing others, showed interest in Kang Jun.Kang Jun, who was subtly ignored by his friends for being weak, didn’t dislike Go Yohan’s interest, but…Eighteen, the period where one’s pride took the lead and held fear of crossing the line.Kang Jun had to make a choice to survive.A very wise choice.