There are some differences.

Temu’s UI is unusable. You are constantly presented with roulette wheels for coupons you can’t dismiss. Its dark patterns have dark patterns. AliExpress is only mildly better in that you can dismiss stuff.

Both T and A still have listings for things that will likely result in you getting something entirely different. This usually applies to more expensive and physically larger items. You might order a greenhouse and get a photo of one or a schematic of one. And I don’t mean that the description will make it clear.

Both have a pattern where they might list let’s say an MP3 player which costs $30 but the price on the listing will be $3 because one of the product variants is just the case.

Amazon has comparatively reliable shipping and it’s included with the price on a majority of products if you have a Prime membership. While Temu and AliExpress do have US-based shipping they still don’t guarantee when the thing will arrive and if you are looking at these products the price difference basically disappears.

I am not defending Amazon by any means, but purely on usability it wins hands down.

Theres also no moral reason to support Amazon, they give nothing back to the society their buyers live in, much like the chinese suppliers. Might aswell just go with the cheapest.

You mean you don't want to buy the finest grade $59.95 blender for your kitchen from LONCEVON or ARVAGGCCY or ADVWUXITEKPRO ?

The tricky part now is identifying the individual CN vendors which are not yet well known in the English marketplace, that are also known to make good quality things (and generally they're not cheap), I'll use Sofirn flashlights and headlamps as an example. Mostly not sold via Amazon.