The canon is anything that appears in the games. There are clear timelines between many of the games, asserted within the game text or game subtext.

Producers have gone on record echoing what's states in the HH, both before and after it was published.

Do not mistake the canon for something the producers and designers feel in any way bound by. That's not what the term means when discussing media.

I mean that's one way to look at it I suppose. However I don't think the story being secondary to gameplay means we have to discount what is there available to us. Like if you want to ignore it that's fine but I don't think you can say it's wholesale not canon.

https://www.zeldadungeon.net/dont_misinterpret_aonumas_words_hyrule_historias_timeline_is_fully_canon/

Edit: also want to say I am not taking this link as gospel, but just showing how the words can be interpreted many ways.

Also the newest timeline is on display at the official Nintendo live event in Sydney, which I would argue is more legit than a licensed book

Regardless it's not really that important, so if people like the timeline, who cares? Nintendo clearly acknowledges it, and the devs don't use it when making new games. Both can be true