Rebirth: Pampered by My Children and Husband - Chapter 1 - "I am your mother.

“No way, Salino, you said that this little guy who killed 300 million pirates in one blow, who is only eight years old this year, is your biological brother?!”

Sengoku Marshal’s office, Akainu, Aokiji, Garp, Sengoku, Crane, all looked confused. “It’s really him!”

Huang Yuan was also shocked and confused, his younger brother was obviously only eight years old, how could he be so fierce? ! At this time, summer is here. Sengoku invited him to join the navy.

“Joining the navy is no problem, I want to be an admiral!”

Red Dog frowned: “General? Just you?” Xia Tian made a decisive move, and sent Red Dog flying with one punch, shocking the audience!

“Yes, it’s just me.”

- Description from novelbuddy

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.

Pick one of the 100 lord characters to be the final winner of the game “Territory Wars”.I became the first person in the world to complete the game using the world’s worst shitty character, Otto de Scuderia.I’m thrilled to see my name in the Hall of Fame, but I’ve been possessed into the game in the body of Otto de Scuderia, the worst of the worst.The memory of the experience is clouding my mind, but…If there’s no turning back, let’s just enjoy it.This time as the real Otto de Scuderia.

CautionTaboo 18+Banished by failure and despair, a virgin loser wakes in a new world with a forbidden power—the Lust System. To survive and claim a rare herb that could save him, he must seduce, corrupt, and conquer hearts across worlds. Pleasure is the key to power…and survival.