These days, the world of romance fantasy is full of transmigrators. There are

scoundrels who steal all the fortuitous encounters and refuse to take responsibility.
Villainesses vying for the heroine's position.
Psychopaths who view humans as NPCs.
And even those who recklessly churn out unheard-of gadgets as if they were wearing a pocket of the fourth dimension.

In a world destroyed by them, the protagonist has returned to the past.