I Have Reincarnated Yet Once Again - Chapter 6: – Aristynne: The Queen of Blood and Reform.

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

Wen Qing was pulled into an infinite flow game, and after struggling through the first instance, he received a strange buff.

System: 【 All non-human beings will have a good impression of you. PS: ***** 】

Wen Qing asked cautiously: ”What do the asterisks mean?”

System: 【 It means ***** 】

The blocked words are definitely not good at all!

Wen Qing cried: ”Can I refuse this weird buff?”

System: 【 The highest-end hunters often appear in the form of prey. 】

Wen Qing choked. ”Am I the highest-end hunter?”

System: 【 You are the most delicious prey. 】

Wen Qing: ???

- 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.