Rebirth Of The Mightiest Disciple (Reboot) - Chapter 665:

Even after knowing what came next....I still accepted.A deal with the devil herself.A devil, in the form of a goddess.I accepted a life that I knew wouldn't end well, a life that was worse off than the very curel one I already lived.But I still choose to do it.I chose to become the villain.

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.

In the Interstellar era where the strong are king, soft and cute species are almost all extinct.

Tu Mianmian, who crossed over, was given a ruthless Duke husband, a husband who could destroy Mechas in minutes.

As a lop-eared rabbit who had just refined his human shape, he felt weak, pitiful and helpless.

So, he resolutely ran into the entertainment circle, relying on his sky-defying appearance to garner large amounts of fans from interstellar society, including his own gong/husband.

It was night, and the Duke who was going to improve the relationship between husband and wife walked to the door and saw a fluffy lop-eared rabbit lying on the sofa…

When Tu Mianmian found himself sleeping beside his gong with his rabbit body stretched out, he scared himself. Sitting up in shock and dazed, he unconsciously stomped the Duke’s mouth. Shivering, he retracted his rabbit paw, but was caught by his gong with a cold face.

Tu Mianmian: …I, I, I am willing to cut off this rabbit’s paw!

Before he could finish speaking, the iron-blooded Lord Duke approached his mouth at the speed of light: Chuu~~ ( ˘ ³ ˘)♥

- Description from Novelupdates