They could, but two years in with most of them and half of the Galarian dex missing gives me little hope for that. :/They have shown all gym leaders till previous gen in the anime. I think they will show the Galar ones as well in the next two years even if Ash doesn't battle them. May be they'll be introduced in the Leon episodes to come.
And who knows we might get all Star Galarian tournament in the anime.