After Transmigrating into a Book, I Became the Strongest Omega

Couple: Natural Little Black Cutie * Scheming Dog Old Fanatic
In the apocalypse, Dong Du picked up a book. After reading just two lines, in the blink of an eye, he transmigrated into the role of the omega younger brother of the emperor in the story.
He thought he could easily win, but the little prince had no father to dote on him, no mother to love him, and even the emperor older brother was devoted to someone else, planning to send him to a border fortress.
Dong Du: ?
No it wouldn’t be, does the little prince have to struggle on his own?
Later, all the enemies were dumbfounded. They came to the fortress to mock the little prince.
But wherever the fortress general went, he took him along. The Chief Defense Fortress Officer personally served him. Fierce interstellar pirates hesitated to harm him. The duke’s younger son, originally at odds with him, insisted on holding hands and watching movies with him. Even the enemy country’s prime minister was willing to exchange ten small planets to marry him.
Enemies: It’s an illusion, all illusions!
After observing for a week, the enemies: Waaah, the little prince is so cute, the little prince can do anything!
However, in reality…
Dong Du: Studying with the general, exercising muscles with the chief officer, outsmarting interstellar pirates, brawling with the duke’s younger son, discussing world peace with the enemy country’s prime minister!
General, officer, pirate, duke’s younger son, enemy country’s prime minister: I’m in a relationship with Dong Du!
Warnings:
The romantic development is slow, and it follows the book’s title; don’t enter if you dislike it.
The plot follows the protagonist, and other characters may be relatively weakened.
1v1
Please bear with any inadequacies in writing.
One-sentence Summary: The omega is the most formidable!
Theme: Face difficulties with strong and unwavering efforts.