I Have Become The Heroes’ Rival - Chapter 69

Lynn traveled to a magical world similar to the European Middle Ages but possessing magical powers.

Here, magic can affect and control elementary particles.

So…a scientific theory is a magic formula!

Wizards called spellcasters who are actually scientists, under the siege of the Holy See, struggled to explore the truth of the world, until the arrival of Lin En, which set off a renaissance of an alien version…

(PS: The 2 million-word work “Hogwarts Bloodline Wizards” has already been completed, and the quality is guaranteed!)

- 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.

Dark purple skies and deathly black clouds herald the arrival of the apocalypse. The earth shudders and groans as the Dark Matter wave mutates the very planet itself, and those within it.Follow Henrick as he fights for the right to survive, and navigates this treacherous new world.

After being given up on by his family because his dantian was destroyed, Soh Woonhwi was kidnapped by the Blood Cult and lived as a third-rate spy.

One day, he died while being used to find a legendary sword immortal’s secret records. However, he returned to the day he was kidnapped ten years ago and obtained a mysterious ability that allowed him to hear the voice of swords.