I'm an Infinite Regressor, But I've Got Stories to Tell - Chapter 300

In a peculiar twist of fate, Lee Taeok, found himself in an extraordinary predicament. Little did he know that his scathing critique of a popular novel, ridiculing its blatant naivety and overly innocent take on romance, would set in motion a perplexing chain of events, ultimately leading to his unexpected rebirth as the delinquent character, Baek Taeyang, from the very same novel.“You should have taken better care of your girlfriend.”In the world of the Academy Sweet Love Diary novel, Baek Taeyang is destined to “rescue” the heroines.

After leaving earth in a pathetic way, Asher finds his soul in the body of a baron's bastard son.As the last surviving member of the Ashbournes, Asher must take up the mantle and build his territory or die in the jaws of a beast or the blades of hungry nobles greedy for his territory.Luckily, he did not enter this man-eat-man world without support.[Ding! Soulbinding successfully completed.][Would the host like to upgrade your bronze-ranked butler to a powerful silver-ranked swordsman? Yes or No.]

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.

Mythical Abode Mountain, Cloud’s End Cliff, the most dangerous of Azure Cloud Continent’s four deadly areas. Cloud’s End Cliff’s base is known as the Grim Reaper’s Cemetery.