The Scum Villain’s Self-Saving System - Chapter 20

Violence, Rogue, two names that had long since faded away from the limelight. In a new game, The Strange World, they appear once again. The two former legends, once more rise to glory.

- Description from Novelupdates

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 was a loser in his past life, useless, but at least he never truly lacked anything. He had money, food, a roof over his head, and everything he thought he needed.He had never fought a day in his life, he didn't need to struggle for his life.Then he got hit by a bus… and woke up in another world.A world where destruction and bloodshed were the norm. A world shattered by apocalypse, where people lived on floating islands and sailed across the skies in airborne ships. A world where the weak had no place to survive.Now, he inhabits the body of a Dragon, the weakest of the royal bloodline. A cursed runt abandoned by his siblings, carrying their curse.He is now known as Kaedros, the Dragon of the Sun.He was banished and thrown into the human territory, to fend for himself in the midst of the enemies that wanted him dead.But now as a Dragon, given a second chance, he didn't want to waste it by being a loser a second time. This time, there's inheritance to claim, territories to conquer and galactic, dimensional enemies to fight._________________So I'm going to add this. The pacing is going to be in the middle, not fast or slow. And the MC won't just get insanely overpowered at the start.He's not going to be a weakling either, after all from the title, you already know how things are going to end.I value character developments, so you'll see a lot of that as well.Things are going to develop in a reasonable way.Ps— you're already adding this to your library, so just start reading now!!

In the early world of immortal cultivation, there was no physical cultivation among immortal cultivators. And a top bodybuilder who came from the earth has opened up a new path here and became the ancestor of physical training.

- Description from novelbuddy