On the same day as Metroid Dread!

Best Buy has relisted the Dark Samus amiibo, with a release date of the 8th of October 2021. The Dark Samus amiibo was first released on the 17th of January 2020.

Seeing that Metroid Dread will be releasing on the 8th of October as well, it might indicate that the Dark Samus amiibo has some functionalities in the game.

Source: Twitter