MTL - The Kryptonian of a Certain American Comic - Chapter 309 103, Justice League

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.

When a glorious old civilization was toppled overnight, a strange purple moon rose and thus began the Purple Moon Era.

Damn it! What kind of ecosystem was this? The evolution was messy. Even rabbit bites and plants were not to be messed with. How can one survive all this? Evolve into a Purple Moon Warrior? What did this have to do with the Purple Moon?

What kind of map was this? The Safety Sector? The Floating Domain? The Darkness Port? The Storm Voyage? The True Capital?

The Horror Lullaby List? The resurrection of the Underground Tribe and the prospering Underground City? The Chaos Black Market that suffused the world? The Bloody Road?

More importantly, one could end up in a bloody slaughter when dreaming and enter the Dream Domain? Fine, this damned era!

- Description from Novelupdates

Yun is a novice MMO player who equipped only unpopular skills labelled as garbage. However, soon after the official launch of the game, the NPCs stopped selling Recovery Potions. Everyone finally started to notice the importance of Support Magic and Items. And that spells trouble for Yun as well as all the other support-based players. They received orders for recovery potion from endless flood of players en masse, some more aggressive players even go as far as forcing the support players to be their personal craftsman. In order to prevent this from going out of hands, all the support players grouped together to form a community to keep things in order.