Rebirth of Billionaire's Wife - Chapter 51: You are my actual business

Lyle Walt is a young noble boy and heir looking forward to the day he can inherit his family’s territory. Except around when he was 10 year old, his parents started neglecting him more and more in favour of his little sister, Celes.
On his fifteenth birthday, he is challenged to a duel by his sister to see who will inherit the household and horribly loses, being cast out of his family. Afterwards, he gets treated by the family groundskeepers and receives the family heirloom Gem from him that Lyle’s grandfather had entrusted to him. From there, he begins an aimless journey with his childhood friend and former fiancée, Novem, and the Gem-turned-Jewel that houses the memories, personalities, and Skills of seven of his ancestors.

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.

The world had started doomsday, and I struggled for a year, before I died under an enchanted beast’s claw. Heaven has given me another chance, back a day before the end happen. Will I be able to change my fate, and that of my loved ones? Now, I will start my journey on becoming the strongest on the planet that the Gods have changed into a game world.

- Description from Novelupdates

A mechanical engineer Poul Nielsen along with his best friend Jonathan Axelsen a civil engineer died after a truck crashed at the coffee shop where they were hanging out and got transmigrated in a late 19th-century parallel world, in the country of Avalonia. It was at the height of the second industrial revolution and to survive daily, they’ll have to work like others to earn pennies to get by the day. However, the two didn’t settle for less. They want to be the Edison, the Chrysler, the Rockefeller, the Carnegie, the Ford, and the Westinghouse of this new world.

This world doesn’t seem to have electricity? Then let’s start an electric power distribution company. Light is not enough, let’s build appliances and motors as well to make our business profitable.

This world doesn’t seem to have vehicles and ground transportation relies solely on horse-drawn carriages and trains. Let’s start an Automotive Manufacturing Company.

Huge infrastructure projects such as metro stations, skyscrapers, bridges, tunnels, and dams? Let’s start a Civil Engineering firm and build miracles in this world.

There is always money in guns, they say. Fine, let's invest in another venture, the arms manufacturing company.

And before we even know it, we will be the richest men in the world. However, the path won’t be easy as fierce competitions are up ahead. Robber barons who would do everything just to crush their competitors. Predator against predator, and government intervention.