MTL - The Emperor Reigns Them All - Chapter 1 Shiko

He is the great master of the Heavenly God Temple, under whom there are thirty-six Heavenly Stars and seventy-two Earthly Fiends, overseeing nearly half of the world's wealth.To uncover the secret of his origins, he holds a marriage certificate and hides away in the bustling city, becoming a live-in son-in-law that others see as living off his wife.His mother-in-law constantly mocks him and disapproves of the marriage, but little did she know that the world's richest man would visit personally just to leave a good impression on him.Ye Guichen felt helpless: Alright, I’ll come clean then...

A teen is summoned to another world as the Hero. It turns out the Hero can power up women with his cum.

The two faced number one female spy transmigrates to a different world and becomes an outrageous idiot girl. When she woke up, what she had to face was consecutive blows of the decline of her family clan, her crippled martial skills, and her disfiguration. To protect her family, she must obtain the treasured book, obtain outstanding achievements, summon a dark beast army. Wait and see how in this unfamiliar, dark magical continent, she dies and becomes a demon then steps up to the top, making all of the formidable people in the world bow down to her in respect.

- Description from Novelupdates

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.