The Regressors are Trying to Kill Me - Chapter 17

Octavius, misled by friends, embarks on a quest to clear his father's name, ultimately facing a tragic end with his sister.Their journey results in devastating loss, leaving him powerless and yearning for revenge against those who harmed his family. Spirits offer him a chance to reincarnate, but he refuses, saying;“What’s the point of a new life if I keep running from my problems”The entities are taken aback by his unwavering decision, having never encountered a spirit who refuses to escape their troubled past. They warn him about the evil being that now resides in his old body, but that only motivates him. He believed In the saying - to defeat a monster, you have to be twice as monstrous.Embracing his fate as The Phantom's Gambit, they traverse the shadowy path of retribution, their identities blur, secrets unravel, and the line between savior and monster fades.This is a tale of darkness and redemption, where justice is a blade, and revenge is the only way forward.

“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

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.

Her first encounter with Qin Sijue is an unexpected one. While trying to hide from her pursuers, she accidentally barges into his changing room. Yet, their paths crosses again fatefully—after a fake marriage, she legally becomes his bride. She imagines that they will only interact before the agreement ends, after which they would have nothing to do with each other. However, Qin Sijue comes over with two red booklets—their wedding certificate. “Take them for an appraisal and see if they’re real”.