Yamato's Devil Fruit awakening before Kaido was already intended in One Piece.
Yamato awakens his Devil Fruit | Yamato vs Kaido | One Piece (English Sub)
The rare ability to awaken a Devil Fruit in One Piece has raised the level of the mysterious power and its user. Each type of Devil Fruit has a unique form of awakening, and the Logia and Mythical Zoan awakenings are ones that fans have rarely or never seen, since the concept of awakening was established in the story.
In fact, in the case of the Mythical Zoan, the only Devil Fruit that has gone through awakening is Yamato's Dog-Dog Fruit, Model: Okuchi-no-Makami. Although it has never been officially confirmed in history, there have been several pieces of evidence to suggest that Yamato has awakened his Devil Fruit.
However, what surprised fans the most was that Yamato had an awakened Devil Fruit, and his father, Kaido, did not. While this is certainly fascinating, there is a theory that explains how Yamato was able to achieve the impossible before his father.
