My Items Have an Upgrade Panel - Chapter 291 - : The Lion Wants to Buy a Great Killing Weapon

The price for saving the world is the right to rule it. After saving a faraway land, Lyn Rivers was cast back to Earth. Wanting the admiration, prestige, and glory of saving that realm, she forced her way back. But she was forgotten, and someone else claimed credit for her deeds. Now, with the power of a deity of destruction, she desires nothing more than to claim her place in history. To do that she will conquer dungeons, make alliances, destroy kingdoms, and build an empire. After all, why ruin the world when you can bend it to your will?

From a media tycoon’s daughter to a poor plumber’s girl, but it seems that Yu Yao is unfazed? She opened the eyes of the sky, and her life has been opened all the way. She is an eighteen-year-old girl, but as soon as she turns around, she becomes a big boss who no one in the entertainment industry dares to offend.

- Description from Novelupdates

After the death of Fu Sinian, Yu Duo’s heart shattered into pieces. As his widow, she was the recipient of Fu Sinian’s massive amount of inheritance. She spent her days drowning herself with alcohol and was depressed all the time. She mourned her late husband with the companionship of her designer purses, designer jewelries, and money that could last her several lifetimes.

But only Fu Sinian knew the truth — that after his death, this woman hosted parties, lived in their mansion, drove expensive sport cars, traveled the world, and flirted with men. She was having the time of her life.

Fu Sinian wasn’t so angry that his soul dissipated; quite the contrary, he was so angry that he had come back to life!

Fu Sinian, who had come back to live, looked at the mourning Yu Duo and smiled devilishly.

“We are on! Watch me make you fall in love with me for real this time!”

- 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.