Hellmode ~Gamer Who Likes to Speedrun Becomes Peerless in a Parallel World with Obsolete Setting~ - Chapter 46Vol. 1 - - The Reward

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.

“Ding! Soulbinding has been successfully completed; you will now head to the Heaven Awaken World.” After hearing this, Zhao Fu’s vision darkened as he fell to the ground.

With bleak prospects in the real world, Zhao Fu’s life is turned around when countless crystals fell from the sky one night, which people could use to enter an alternate, game-like world. After obtaining an ancient Chinese empire’s legacy, Zhao Fu uses his intellect and resourcefulness to develop his own empire from a tiny village. However, with enemies both in the real world and in the Heaven Awaken World, he must make brilliant decisions and use creative schemes to survive.

- Description from Novelupdates

After the death of Fu Sinian, Yu Duo’s heart shattered into pieces. As his widow, she was the recipient of Fu Sinian’s massive amount of inheritance. She spent her days drowning herself with alcohol and was depressed all the time. She mourned her late husband with the companionship of her designer purses, designer jewelries, and money that could last her several lifetimes.

But only Fu Sinian knew the truth — that after his death, this woman hosted parties, lived in their mansion, drove expensive sport cars, traveled the world, and flirted with men. She was having the time of her life.

Fu Sinian wasn’t so angry that his soul dissipated; quite the contrary, he was so angry that he had come back to life!

Fu Sinian, who had come back to live, looked at the mourning Yu Duo and smiled devilishly.

“We are on! Watch me make you fall in love with me for real this time!”

- Description from Novelupdates

A one-night stand was all she wanted. A one-night stand was not his style. Still, they ended up together in a night of passion. No names, no feelings, and no complications.

They thought that their unexpected encounter was an isolated incident. However, fate had something else in mind.

As they found each other, back in each other’s arms. Not in a passionate embrace, but with a contract that would bind them for a long time. An agreement they were both bond to honor.

Daniella Hamilton was an heiress who wanted nothing to do with her father and her inheritance. She pursued her career to become a lawyer for the masses who could not defend themselves from the injustice in their current judicial system.

Alexander Princeton, as the name suggested, was a possible heir, next in line to his father, the Duke of the Blackstone House. He also wanted nothing to do with the title or the prestige of the dying Royal Empire. To him, wealth was the real power.

Would their agreement lead them to the fulfillment of their dreams or would it end up in a disastrous union?