I wouldn't trust any of those, and a quick search on the amazon.ca didn't show any reliable ones.

If you look in the US Store, you can see this one:

https://www.amazon.com/Valve-Handheld-Console-No-Operating-System/dp/B0BBQRYN9M/ref=sr_1_2?keywords=steam+deck&qid=1684118334&refinements=p_36%3A30000-&rnid=386453011&sr=8-2&ufe=app_do%3Aamzn1.fos.5137e923-c7be-4142-979c-7c68b6c26f63

It's $983 for the 512GB, but it ships from the Amazon warehouse, so Amazon will guarantee delivery to you from their warehouse.

For a more reasonable option, here's the 256GB for $676:

https://www.amazon.com/Steam-Deck-256gb/dp/B0B7KFFKT5/ref=sr_1_5?keywords=steam+deck&qid=1684118409&refinements=p_36%3A30000-%2Cp_76%3A1249140011&rnid=1249138011&rps=1&s=videogames&sr=1-5&ufe=app_do%3Aamzn1.fos.5137e923-c7be-4142-979c-7c68b6c26f63

Usually, you can sort by "Eligible for free shipping" and the results should all be ones that ship out of an Amazon warehouse.

Just note that while you will most likely get a legit Steam Deck, that doesn't mean it's not immune to hardware defects that can happen even when getting the device directly from Valve. So you've got to have a plan in case it doesn't work right out of the box.