Harem Lord System: Post Apocalyptic World - Chapter 37: Natural

Arthur Grail, a hardcore player of the VRMMO Trinity Star Online, woke up one day in the body of Gerard Astoria—a petty villain fated to die before the main story even began. To make matters worse, Gerard's death was a crucial event in the game's narrative. If he didn’t meet his predetermined end, it could disrupt the story entirely, leading the universe toward one of the countless “bad end” routes!Unwilling to leave his fate to chance, Arthur decided to take matters into his own hands—recruiting the “player” as his partner to help him clear the game and rewrite his destiny.But wait—“Why is the player not a dude but a sharp-tongued beauty instead?!”Follow Arthur's odyssey, filled with trouble at every turn, as he works to uncover the mystery behind his awakening in a universe eerily similar to Trinity Star Online's setting, all while trying to save the entire universe… without forgetting to enjoy himself!

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.

She is an expert in medicine, the only daughter of Yun Tian, Yun Valley’s master.

Her parents died, leaving her alone in this world. She fell from heaven to hell. She had a marriage prospect but her future husband broke it off. The entire world view her as a joke.

She blossoms in Feng Yun Hall, with unparalleled wisdom and startling beauty.

Against all the people eager to make a move, she lifts her hand first. Kill the chicken to warn the monkey.

But nobody knows that the soul within her has long been replaced by someone from another world.

She has no regret in the past life and originally plans to live an idyllic life, but because of the same question from the past life, she gives up the peaceful life and steps into the power struggle for imperial power.

- Description from Novelupdates

The Special Investigations Unit is a covert organisation that no-one in the city knows about, dedicated to investigating bizarre occurrences beyond the comprehension of the living. The Chief Zhao Yunlan isn’t a simple guy either, being the inheritor of the Guardian Order, he has always been a righteous conformist, excelling between realms of the living and the dead. While investigating a school suicide case, Zhao is attracted to the calm and reserved Professor Shen Wei, but the Professor seems to be rather fickle towards him…

- Description from Novelupdates