You, CEO's Secret Wife - Chapter 710

Regaining the memories of his previous life, Cyril realised that he was an otome game’s character, the villainous daughter– Sophia’s butler.At the rate things were going, Sophia would eventually have the prince stolen away from her by the heroine, fall into darkness, and be executed.Wanting to save the villainous daughter he was so fond of, Cyril moved to eliminate all the factors that would cause her to fall into darkness, raising her up to be a talented and beautiful girl who could win the prince’s love, however…

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.

It’s an anonymous community; please don’t get your identity exposed.

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!