Seems in this case they got own domains and independent stores.
And Aliexpress and Temu are very different. Aliexpress seems to be a halfway decent platform. Never had any major issues with them, except what's to be expected when importing stuff from China. I think it's very similar to ordering the same thing on eBay.
Temu isn't. That platform is made to harvest data and prey on their "customers".
And I can't comment on Wish. I haven't been interested in cheap crap.