Awakening: My Yandere sister is obsessed with me - Chapter 20: Again

In her previous lifetime, they had married for five years. He meant everything to her, but she was thrown away like an old shoe.

After her rebirth, she gave him a divorce contract preemptively—

“Divorce after one year, the terms of the contract are as follows: husband and wife shall not share a room or bed. Intimacy forbidden?”

He raised his eyebrow.

Who knew that after she got drunk one day, leaning on the headboard, he rested his deep-set eyes on her. “You broke the contract, Mrs, Li.”

- Description from Novelupdates

The protagonist transmigrates into a novel and gains a system where they grow stronger by simply writing in a diary.July 7th, sunny: “The boss’s outfit is hideous again. Wouldn’t it be better to wear something cooler?”July 7th, evening: “I’m about to have my engagement called off. So excited! How should I act?”July 7th, evening: “Lin Qingyue, the female lead, is probably going to drown her sorrows in alcohol.”The protagonist thought it would be easy—just jot down daily musings, record life’s events, and earn rewards. All while playing the part of a villainous, bootlicking second-generation rich kid, moving along with the original plot.But unexpectedly, the female leads gain access to copies of the diary entries.One by one, they stop following the script, and the plot spirals completely out of control.July 10th: “The female boss is an idiot—no one would want her.”Soon after, the protagonist gets punished at work, all because they entered the office with their left foot first.

“201th, 202nd…”Zhou Can, an Intern of Tu Ya Hospital, a Grade A Provincial Tertiary Hospital, would silently count every stitch he finished.His target today was to complete 300 stitches and fight for a place in the House Officer recruitment two days later.[Congratulations on completing your 100,000th suture and triggering the EXP system. Medical skills and surgery practice can be obtained.]Zhou Can shook his head hard.What the hell is this?Something even more magical happened as he thought about it.An interface appeared in front of him.[Zhou Can, Intern.][Pathology Diagnosis, Level Two. Current EXP: 89.5/100. Outstanding House Officer-level diagnosis ability.]A surgical legend was in the making.

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.