Building an Empire in Game of Thrones (REWORKED VERSION) - Chapter 77: A Surprise Proposal from The Vale

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.

Princess Leah wrote a suicide note ahead of her wedding.

The protagonist, Winnie (文尼), confesses his love to his childhood friend—the princess he’s been secretly in love with for years—but is brutally rejected in public. His heart shatters, he’s humiliated and ridiculed, and he collapses unconscious. When he wakes up, he vaguely remembers his past life’s memories and realizes he has transmigrated into the world of an otome game he played before. At first, he’s thrilled, thinking, “Nice! I must have been reincarnated as a villainous side character who disrupts the protagonist’s romance, right?” But then… surprise! He’s not just the villain—he’s the “Saintess”!

Qinghe County master Gu Sheng died. She had a first class beauty, her name could move the world, but she still lost to the hands of a woman inferior to her. Gu Sheng was only able to understand that she was the antagonist of the heroine after her death, a cannon fodder.

In a pure white space, Gu Sheng was expressionless because of the transmigration.

System: “The heroine must change her fate, must fight against cannon fodder and the passerby to brush a sense of existence. As the master, you are their biggest stone in the way.”

Gu Sheng’s eyes flashed and made a peerless smile, “Then let me see who is the stumbling block that should be trampled and who is the final winner!”

- Description from Novelupdates