Novel's Extra: I Awakened The Strongest Physique From The Start - Chapter 309 - Duke Thornmere.

Apollo was a genius who was talented enough to achieve big things in his life, but because of a rare genetic disorder, everything came to an abrupt end.But when he thought everything was done, he again opened his eyes to another world as the baby of a noble family. Knowing that this might be his second chance, he decided to do everything he could to create a good and free life for himself.But surprisingly, this world is not simple, as there are beings with extraordinary power who can control the lives and deaths of others, giants who can crush mountains, dragons who can burn the seas, and many more. So now, to truly achieve his goals, Apollo needs to learn and adapt to this new world where life and death can be matters of thought.

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.

Mimizuku, a small girl with chains on her wrists and ankles and the numbers “332” branded onto her forehead, wanders into the Forest of Night seeking to be eaten by a monster. However, when the ruler of the monsters, the mysterious and beautiful “King of Night,” refuses to eat her, she tries to formulate a way to convince him otherwise.

James Woodrow has transmigrated into a strange world of magic as student in the prestigious Ainsworth Magic Academy. Oh and with him came the gigolo system. Watch how he navigates this strange world full of conspiracies while putting the system to full use by getting all the most beautiful MILFS on the campus.