Dimensional Overseer: I Can Manipulate DNA! - Chapter 20 – Accord

In Ten Heavens Domain, full of respected powerhouses, juvenile Ling Tian accidentally obtained a mysterious iron sword. He refined the Supreme Martial Dao, studied the Divine Spirit Array Laws, fought Ten Thousand proud and arrogant Heavenly Clans, and was undefeated! Seven Feet Sword Tip sweeps away the world, within the Ten Heavens, I am the Supreme God Monarch!

- Description from Novelupdates

18 and naive, Belle Hart thought marriage would end her misery, only to realize it had just begun!What started as a promising love turned out to be a facade, would Belle choose between a second chance or leave? She met her mate, the Duke, who she proposed to when she came of age.A month in, things took a turn. The Duke leaves for war before she could inform him about her pregnancy, only for him to return with a mysterious woman whom he claimed to be his new wife! The audacity! Trouble ensued and Belle suffered a miscarriage as a result.…“What did you just say?” He asked, his gaze darkening.“You heard me well, I seek a divorce. I wish for us to go our separate ways,” she replied, her voice steady as she met his gaze with confidence, though inwardly she was shaken by his presence.“You are my mate, Belle, and I am yours. Divorce is the most foolish notion you could entertain. Do you believe any man would take a worthless creature like you as his wife?” He scoffed, his words biting, causing her heart to ache.…The Duke's refusal pushed Belle into the arms of the king. All she had to do was bear him an heir and he would help her get her revenge!“I want you to marry me, Your Majesty, and aid me in seeking my revenge against the Duke and those who have wronged me. In exchange, I shall bear you an heir before you help me,” she said, her voice steady and full of purpose.What will the choice be?

This is a story of a modern man returning to ancient times, returning to a real world without any extraordinaryness, and slowly rising by relying on the ability to attribute all data.

- Description from novelbuddy

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.