Look, I'm aware your post was a troll to begin with, you surely got into this for the sake of contradiction, that's fine. Still if you're genuinely considering how "official" the game is among other Zelda games, you could just inform yourself, for example: https://nintendoeverything.com/hyrule-warriors-age-of-calamity-devs-on-how-the-game-came-to-be-nintendo-wanting-it-to-be-a-new-experience-more/

I already gave you the intro video, timestamped, where KT's producer tells you the Zelda team was behind this. He also mentions Aonuma coming up to him. The interview confirms that. They wanted to tell the Great Calamity, which is originally BotW lore, and they did.

If you absolutely need to stick at calling that a non-Zelda game, or not canon, have fun. I've indulged enough wanking over labels, I'll stick to an accepted definition of canon): the material accepted as officially part of the story in the fictional universe of that story.

It is an official story, officially initiated and built with the official team, officially marketed and told with an official connection to the official BotW lore it expands. Not sure that's official enough for you. They don't use the word "canon" after all. Yet it is.