The Lycan king - Chapter 39

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.

Known as the youngest academician-level senior engineer, Zhao Guoyang was reborn in the 1990s. In this era of economic globalization, with his extraordinary wisdom and extraordinary insights, he created one miracle after another and became a name that shocked the world!

Wisdom is condensed every bit, brilliance is created by sweat, and witness the rise of a great power!

- Description from novelbuddy

In the spirit of love and in order to help his ex-boyfriends walk out from the shadow of heartbreak, every time before Ye Ming leaves after successfully completing each world’s romance mission, he will ‘kindly’ (ruthlessly) break up with with his boyfriend.

After transmigrating to N different worlds he had finally gained enough experience. At this time the system informed him that because the accumulation of his ex-boyfriend’s grievances had exceeded critical levels, leading to the failure of all his missions…. So he needs to return to each world to eliminate their grievances if he wants to complete his missions!

Ye Ming: This is an outcome I didn’t predict.

System: I tried to tell you before that if you did this you won’t have a good end.

The ex-boyfriends all laughing coldly: He He. That despicable scum that ran away after deceiving my feelings is finally back. This time don’t even think about running away!

Ye Ming: ……

System: Since you “zuo” yourself to death, even if you kneel you have to go to the end!

Ye Ming: Luckily I have a special “scum cleaning” technique ^_^

- Description from Novelupdates

A story of Gin, a young man who lost his memories before the age of 17 and became a magician. Living a quiet life running a cafe while researching magic, he is suddenly thrust into an unknown world. Moving between Earth and a realm filled with danger and secrets, Gin must rely on his knowledge, skills, and magical prowess to navigate the perils that arise. Ruthless and determined, he will stop at nothing to uncover the truth behind his lost memories and the mysteries of the world, using every tool at his disposal to rise above all