I was Caught up in a Hero Summoning, but that World is at Peace (WN) - Chapter 1: The Other World Was At Peace (Part 1)

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.

He mocked the omegaverse. Now he’s living it—with a baby on the way.Souta Tachibana was just your average, overworked office drone—until his BL-obsessed coworker introduced him to a trashy omegaverse romance novel. Curious (and a little horrified), Souta read it for laughs. But then he died in an accident.Now, he wakes up in the body of Lucien d’Armoire, a minor noble in the empire of Aetheria. No plot relevance. No destined lovers. Just a quiet, boring life as a background beta.Until one morning, he throws up into a chamber pot… and his doctor says something unthinkable:“Baron d’Armoire, you’re pregnant.”Which is impossible.Because he's male.And straight!And because Betas can’t get pregnant.…Right?Except Lucien is no Beta. He’s a rare male Omega. Apparently, during one reckless, drunken night, Lucien slept with an Alpha. Now he's pregnant, confused, and definitely not ready to be a father. To make matters worse—he doesn’t even know who the father is.

I was reincarnated as the heiress of a conglomerate in the novel. However there was a problem, this world was about to be destroyed by a virus monster. All I have left is money, I quickly bought in the countryside and built a shelter to avoid monsters…The world went down much faster than I expected, f*ck! And somehow, even the male leads are trapped with me in my house. But it doesn’t seem like these two wanted to leave. Why is it as if you guys have no intention of going to the female lead? “What the hell are you?” “I think she knew about the fact that the world would be destroyed.” They had a lot of questions for me but I couldn’t answer them. It’s not like you’re going to believe me anyway, right? Now, in my eyes, they just look like good manpower resources. “Now let’s get to work, pay as much as you eat!” If we manage to find a cure for the virus, the cause of the world’s collapse, our hellish times will be over. So, let’s roll the male leads until then and hold out! But there’s one problem. This old mansion I bought turned out to be quite suspicious. What the hell is going on in my house?

Alternative Title: Crossover: Mangēkyo Sharingan In A Cursed World===Support and read advance chapters at: Patreon.com/Zexxxxy====When he woke up, Ryuu found himself in the body of a high school student.His school was an unusual merger—Soubu High, Toyosaki Academy, Shuchiin Academy, and Totsuki Culinary Academy had somehow combined into one.At first, he thought this was just a typical anime slice-of-life setting. That was until he met Miko Yotsuya from the class next door.From that moment, everything started going wrong.Monsters. Ghosts. Curses.The world he thought was normal was anything but. Strange and terrifying entities that had no place in daily life kept appearing.Fortunately, Ryuu possessed the Sharingan, and he soon discovered that negative energy could be absorbed as fuel for his eyes’ evolution.The more horrors he faced, the stronger he became. Step by step, he walked the path of exorcising spirits while growing into an unstoppable force.But as his strength grew, so did the number of extraordinary and beautiful girls drawn to his side…---Miko Yotsuya: “Please help me, Ryuu-san.”Mai Sakurajima: “You’re the only one who can see me.”Utaha Kasumigaoka: “Surrounded by beautiful girls… is this how you plan to revive your clan?”===================================Worlds Included: Jujutsu Kaisen, Rascal Does Not Dream of Bunny Girl Senpai, Saekano: How To Raise A Boring Girlfriend, Mieruko-chan, Oregairu & more.====All rights belong to the original authors, I am just a mere translator that's translating this because i loves the idea, the story.