Progenitor Vampire: I Have Many Skills! - Chapter 282: You are mine.

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.

Akira Kisaragi traverses into the Bleach world, unlocking a check-in system.He initially thought that by checking in daily, he could become stronger, soon become the Captain-Commander, join Division Zero, punch Yhwach, kick the Soul King, and marry Unohana...However, the system's style wasn't quite what he had imagined.〈 Check-in complete, obtained Genryūsai Yamamoto's secret roasted sweet potato! 〉〈 Check-in complete, obtained exclusive attribute: King of Normal Attacks, effect... 〉〈 Check-in complete, obtained Retsu Unohana's... 〉Akira's eyes suddenly lit up!“Seems like this might not be so bad after all!”

Someone once saw me at the end of the world and respectfully called me the serpent that coils around the world—Jörmungandr.Someone once gazed upon my form at the edge of the Underworld and called me an ancient serpent—Satan.I was also feared by the gods and was called the hundred-headed dragon—Typhon.I have had many names—the serpent of creation, the serpent of sacrifice, the serpent of ceremony, the serpent of the world...But I have wandered through the chaos and arrived at the wilderness. There is only one divine name—the Primordial Ancient Serpent, the origin of everything.

Enter a world of superhuman abilities and mysterious organizations as you follow the story of Jiang Bei, the enigmatic founder of the Infinite Alliance.With the power to extinguish stars and melt anything in his path, he is hailed as a god among men and the torch of the Dark Era.But what secrets lie behind his incredible powers, and what will he do to protect his legacy and extend his life?