Question: are the legendaries shiny locked in sword and shield?
Answer: Dataminer Kaphotics revealed today that the starters—Grookey, Scorbunny, and Sobble—and the legendary Pokémon in Sword and Shield will not to appear as shiny in the overworld. As usual with models shown in the overworld, the legendaries and starters you can obtain in-game are shiny locked.