Reich Marshal of the Belkan Reich - Chapter 305: RM Vol 4: War – : Case Yellow (Day 2 - Return to Sender) - Edited by Yovis

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.

Li Xuehao found a secret of monasticism in the cover of the genealogy. After spending ten years, he finally succeeded in building the foundation. Unexpectedly, he was eager to get rid of the evil spirits. After his death, he was born again in Yokohama, Japan, and was attached to Sakura, Tsurumi. The story of the high school student Gao Zhonghao in the college, the story begins here…

- Description from Shubaow (Translated)

A young love leads to a lifetime of entanglements. Zhao Mo Sheng is a university student with a sunny disposition. The bright and cheerful Mo Sheng fell in love at first sight with He Yi Chen, one of the top students from the Law Faculty. However, his poor communication skill, makes her depart sadly for overseas. Seven years later, Zhao Mo Sheng returned home and spotted him immediately in a crowded supermarket, …….

This is a very short and sweet story about two college sweethearts, who separated on a bitter note but fate tosses them together again seven years later.