my 2c...
Most brands who uses Chinese manufacturing have long since learnt how to protect their IP. Most of the stuff you find on Aliexpress that mimic other products tend to be one of a few things. Rejects from QA used to be a big one until recently. "Mountain villa factory" specials, or basically straight up knock off copies (most often badly). Stuff that is "mistakenly" labeled to seem like something else. Accurate product descriptions are not really a thing over here, totally buyer beware.
For the Mishi clone, if you look through their original testing / development thread, they did try a bar and plate cooler of that size. Is it the same one? I don't know. Their testing did show significant pressure drop for two of the bar and plates they tested. For the Cobb clone, stick a bore scope and compare the fins between the branded one and the unbranded ones. They are most definitely not Garrett cores. Most would not want to copy Garrett because of their fin design, way too high cost to manufacture. If they did, they would most likely use it as a selling point. "Garrett style" or "stagger fin" or "high density fin" for example.
I have no issue with the cheap stuff, if you want to run something that didn't have much R&D, that's fine, just call it what it is. The really good stuff is usually well protected, there aren't really any "hidden gems for cheap".
TL;DR: cheap Chinese copies are exactly that, buyer beware.