Unscientific Beast Taming - Chapter 1937 - : Why Another One (1)

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.

When the rifts between worlds opened, countless monsters flooded through, engulfing human cities and plunging the world into chaos. Faced with this apocalyptic crisis, humanity was forced into a new era where every individual had to choose a profession. Nations now compete to cultivate elite practitioners, striving for supremacy in the rankings of alternate world conquests.But as the world teeters on the brink, the first and greatest champion awakens after a million years of slumber—armed with untold buff amassed from his millennia of AFK grinding.The bosses of the otherworld tremble in fear. Global T0-ranked powerhouses bow down, offering their loyalty...[Disclaimer: Here countries fight against each other and this is adapted into a Manhua.][Schedule: 2 Chapters/Day]

As soon as Lu Xuan woke up, he became an ordinary spiritual planter in Sanxiufang City, guarding a one-acre three-point spiritual field, and living in the world of practice.

Fortunately, I accidentally discovered that every time a spiritual plant matures, I can get extra rewards.

Harvest a sword grass and get a sword pill.

Harvest a Xuan Chong vine and get a share of Yin Xingsha.

Harvest a Youquan flower and get a piece of Zhiyan Pill Recipe.

…

From then on, he guarded his spiritual field peacefully, and sat and watched the world of practice turbulent and vicissitudes.

“What about fighting skills, exploring secret realms, seeking immortal fate, obtaining magic weapons…all have nothing to do with me!”

“I just want to farm quietly.”

- Description from novelbuddy

One of the six people called heroes, Raid, fought alone against the Devil, and ended up dead.

After meeting with a suspicious god, he woke up again and found out he has born again as a baby.

Moreover, as a daughter of his former companions.

In order to regain his former power, Raid/Nicole has to go through a life of hardships to reach the ideal he aims for.