MTL - Reincarnation For All: One-click Tracking, One-click Full Level - Chapter 45

One day, a tower appeared in the skies of all the major cities…

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.

The 5,000 years-old boy has resurfaced!In the distant past, young and foolish Asley flunked out of the prestigious Magic University… by failing an early exam that had a 100% passing rate until then. Shortly afterwards, he accidentally created the immortality-granting “Drop of Eternity,” and upon consuming it, obtained an eternally lasting body.He devoted himself to researching magic for almost 5,000 years… after which he traveled in search of the world’s most mysterious Dungeon. Along the way, he happened to save a family, and then their town, from a monster attack. Before he knew it, he was hailed by the locals as a savior with ancient arcane arts and knowledge…While helping to rebuild the town, an opportunity came up for Asley to enter the Magic University once again, so he did. One thing led to another, and his initially normal journey got bigger and bigger — studying, adventuring, monster hunting, money-making, hellish training, uncovering conspiracies, saving the world, the whole nine yards!Thus began the adventure through the mundane and the insane of “Eternal Fool” Asley, his Familiar wolf-dog Pochi, and all their friends and enemies along the way!

I became a scientist for an evil organization.…But I’m too competent.