They are, I would never trust any storage on Temu or similar sites. You see people making articles and videos about those scams all the time, ESPECIALLY if they sound too good to be true. It is very very easy to hack the controller on flash/nand based storage like SSDs or SD cards to report a false amount of space, the drive will appear to work normally until you hit it's actual limit, after that files will start to go missing or become corrupt. I have even had expensive products like 3D Printers that arrived with a fake SD card.

On a lesser scam, some might sell a NVME that has the proper amount of storage, but is QVC instead of TLC so it wears out much faster or claims it has DRAM but lacks it, causing speeds to slow down if you transfer data heavily on it.