Dungeon Diver: Stealing A Monster's Power - Chapter 7

After marriage—On Valentine's Day, Han Jingnian asked, “How are we spending today?”Wrapped up in her blanket and close to falling asleep, Xia Wan'an mumbled, “Sleep.”On Christmas Day, Han Jingnian asked, “How are we spending today?”With her arms around her pillow, Xia Wan'an casually replied, “Sleep.”On their wedding anniversary, holding a cup of water, Han Jingnian asked, “How are we spending today?”Cozied up in bed, with sleepy eyes, Xia Wan'an looked at Han Jingnian, wary of the water he might spill on the bed. She thought for a moment, then replied, “With you... together.”

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.

The day of marriage. Lifting the sedan chair to the door, he lightly lifted the sedan curtain, but he saw no newcomer, only a piece of paper pressed under a stone.

Looking at her flamboyant font, his thousand-year-old pupils faintly spurted out a few flames. good very good. On his perfect and impeccable face, there was a faint smile, not angry but smiling.

However, no one saw the hidden chill in that smile. That woman dared to run away from marriage, he would let her know the consequences of doing so.

- Description from novelbuddy

Hai Xiu has a slight social disorder. After he transfered school, his new teacher tried to help him to treat it slowly by giving him the task of sending and receiving homework and test paper from his fellow classmates. Although Hai Xiu has communication problem, he still stumbled around trying his best to do so. However, he accidentally misplaced the test paper of the school’s resident “bad student”… And thus, started their sweet story together…

- Description from Novelupdates