My Sassy ‘Crown Princess’ - Chapter 16 - Dowry

In a mass ambush at the Battle of the Gods, the four major guilds with all their armies surrounded one man alone: McRae, known by all players as the God of War.

But even the God of War could not survive alone against hundreds of attackers.

Yet, when McRae opened his eyes again, he’d returned to the first-day launch of the game, [Divine Domain]- and he still had his full-level character, with all classes available to him to switch freely between at any time.

With all his previous memories, McRae knew that their entire world would soon merge with the game world, where death would become permanent… And so he turned on Divine Domain once more– this time fully aware of every detail about the players, the treasures, and the game itself.

Before the four guilds were even formed, McRae would have a guild and an army of his own.

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.

Jiang Bai woke up one day and found with shock that he had transmigrated to a parallel world that is similar to Earth. There, he was granted a cheat system to help him forge the path of a tyrant in this new world. He was now stuck in this parallel world body, the body of a weak and cowardly person. Join Jiang Bai as he rose to the top in this new world!

- 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.