Astral Pet Store (WN) - Chapter 1047: Return Of The Dragon King

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.

Ten years ago, mana descended upon Earth in the form of Gates that opened into other worlds. These Gates contained Magical Beasts of unfathomable strength and power that preyed upon humans and sought the destruction of everything around them.But along with the Gates, humans gained the power of Gifts—super abilities that allowed them to fight back against the monsters and take back their world.Now, the Superhumans with Gifts are tasked with defending the people and ensuring that the Gates, which open all over the world, do not bring about the end of them all....Jason Marc was just your regular seventeen-year-old high school student whose father abandoned him ten years ago. He worked two part-time jobs while also helping his mom with her diner to aid with the finances, but he could have never guessed that his entire world would change on the eve of his eighteenth birthday.Now, with more power than any one man should possess and an army at his beck and call, Jason works toward protecting those close to him while finding out the truth behind the emergence of the Gates—and preventing the end of the world.

Arthur Blackwynd didn’t expect to survive the strange and terrifying event that happened at sea. Even less did he expect to wake up in the DC Universe a world he’d only ever read about in comics.Armed with the Shadow Monarch System,the ability that grants him control over shadows and an undead army, Arthur is both awed by his new reality. As a lifelong comic geek, he knows the heroes and villains like the back of his hand Haunted by questions of why he’s here, Arthur struggles to find his purpose. Will he embrace the darker side of his newfound powers and become a villain, or will his sense of justice lead him down a different, unpredictable path?“why the likes of Raven seems to be watching my every move?” In a world full of gods, monsters, and legends, Arthur must decide who he will become and what role he’ll play in shaping the fate of the DC Universe.

After being killed, Xu Turan was given a system and got pulled into a certain thriller romance novel. There, she became the crucial female supporting role who seeks death. However, on the first day of transmigrating, her system was urgently recalled for repair as it was aging.

As their farewell was imminent, the system was worried about its new host so it repeatedly reminded Xu Turan: [Your role is to be a supporting character who is always seeking death. You do know what that means, right?]

Xu Turan recalled her rich experience of doing just that in her previous life and she replied affirmatively with absolute confidence.

So the system withdrew with its mind at ease.

After a few days, the system that had been away for repair finally returned. When it looked at the situation, it almost malfunctioned: [What are you doing?!!]

Xu Turan, who was busy arguing with the Evil God, answered without thinking, “I’m doing what you asked me to do – trying to find ways to die.]

System: […?!]

- Description from Novelupdates