For various things (certain electronics/peripherals, certain tools) I deliberately avoid Amazon because I want something I can trust and don't have energy to decide which of the fifteen similar-looking things on Amazon is well-made and which is a fake or just crap.
That Vietnamese company with the 3x capacity:price ratio is probably selling junk. There are just so many more junk sellers (at least by name—maybe a handful operating all those names). So it boils down to taking a gamble when the odds are against you, getting lucky, and building a relationship or going to a retailer you trust already.
I've had great luck in these situations buying from a small company that filtered out which cheap brands were good products. However I already have some other reason to trust those small companies.
You also can tell low quality products for the poor English/Grammar and knockoff similar brand names.
Amazons search really sucks quiet often a long tail search term will return product that in no way matches searcher intent.