The Runesmith - Chapter 460: Unusual Getaway.

Mu Yangling was reborn in the family of Orion. He thought he could live a simple and happy life. Who would have thought that a military disaster had nearly destroyed their family. His father was classified as a military household, and their family accompanied them to farm the fields.

Unfortunately, they could not even tell the seedlings of grains. Qing, looking at his mother and younger brother who were about to cry without tears, Mu Yangling raised his chest and said, “It’s okay, I have the strength” and some agricultural theoretical knowledge from a thousand years later.

- 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.

Jack Somnus was a mid-wealth professor of economics and a trading advisor for the powerful Johnson family. But after years of working for the Johnsons, he was abandoned without a word. He was laid off without as much as a severence package. Jack’s life got worse when he lost his wife. Depressed and alone, he got into an unfortunate accident. Instead of dying, he travels back in time to his teenage years. Now, Jack has a second chance to live the life he always wanted. He wants to be the one who controls, not the one being controlled. But his time travel hides a deeper secret, one that might throw him for a loop. [WARNING: CONTAINS EXPLICIT EROTIC SCENES]

Miracles don’t come walking your way by themselves.