MTL - Aztec Eternals - Chapter 4 city-state

An unexpected discovery in Machu Picchu has transported a young professional thief from Earth to a world filled with mystical powers and evil plots. With his beloved teacher and best friend killed during the calamity, his only goal is to become stronger, so that he can take revenge for them.This is a novel filled with politics, the struggle for power, evil beauties, and of course, Divine Immortals.

- Description from Novelupdates

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.

Guns suppress all divine demons and evil spirits, flesh and blood forge the multi-dimensional Great Wall!In the second year of Ming Country, Tianmen City was in need of recovery after the war. Chaos thrived, and evil spirits roamed freely.The children of the poor take charge early, and garrison soldiers need to learn to earn their own money.My name is Wang Yunxiao, an external field agent for the Special Service Bureau, specialized in dealing with various demon and evil spirit emergencies locally.Let me introduce my wife Li Mumu—she is gentle, virtuous, cute, and empathetic, and she is an evil spirit.Who writes a diary in all seriousness! Can what’s written even be considered true inner thoughts? Despicable!(The female protagonist’s solo storyline begins later, starting from chapter 87)

After traveling through time and space and becoming the younger brother of Uchiha Fugaku, Uchiha Yuto felt very panicked! He was preparing to practice hard to become the God of the Ninja World and suppress everyone, but after graduating from the Ninja Academy, he suddenly discovered that he had another path to take!“Itachi, don’t be a ninja; be a prodigal son! Uncle will give you money. The more you spend, the more popular you will be.”Being a ninja can't save the Uchiha! — Uchiha YutoThe more money Uchiha Yuto makes, the stronger his abilities will become!