Seven Sins System - Chapter 373: Blame It On The Devil

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.

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure–-did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the nation! What’s more, he’s betrothed to the king’s daughter now…?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side. Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess…?! What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!

Su Yao passed through and traveled to the Marvel world to become a mutant. He was still in the experimental base. He expressed a little panic…

Fortunately, at the critical moment, the mutant ability ‘imitation’ was awakened to imitate the opponent’s ability!
…
Imitation object→Orochi (title: Sun God, Will of the Earth)
Imitation object→Wanda (title: Scarlet Witch, owner of chaos magic)
Imitation object → Sun God…
…
Professor X: “We must find him as soon as possible and guide him to control his power to avoid causing irreparable disasters!”
Magneto: “You are my child???”
Thor: “Brother?”
Loki: “?”

- Description from novelbuddy

The 27-year-old genius beauty doctor Xia Qing dies in surgery!She is reborn!She is reborn in the ward she's most familiar with, in the body of a 200-pound pregnant woman—a woman who had died from pain during a Cesarean section due to her requests to not use anesthesia.She can't help but worry about herself. This body was useless except for being young.How could Xia Qing tolerate this?On the menu are—revenge, losing weight, and snatching the idolized man of a scumbag girl in passing. Although she's overweight, she strives to live well. Being overweight isn't the end of days. They still deserve love.“Have you heard? Boss Pei has a child out of wedlock. He's getting married!”“Who's he marrying? Who?”“That 200-pound fatty from the Lin family of South City!”“Is Second Master crazy?”Lin Xiaqing turns her head to look. “You think I'm fat?”Pei Zhengyang looks at the voluptuous woman. “Not at all, just nice to the touch.”