Hoyoverse x Ufotable

Genshin Anime announced:

The newest colaboration between Ufotable, well known for animating the Kimetsu no Yaiba (Demon Slayer) serie, and Hoyoverse, Genshin creator, has officialy been formalized.

You can say the trailer counts as a formal video even if it is about a videogame because it is not something that was published by a fan or someone unaffiliated. It comes from the official Genshin account in Youtube. So it is verified as a legal, real and trustable video of information.