A lot of devices on Aliexpress advertise false specs. I'm batting about 50/50 for web cams. Half of the ones I got had 640x480 resolution, despite advertising 720p, 1080p, or even 4k....
The other half are awesome.
Two even look identical, but one is 640x480, and horribly bad resolution at that, while the other is around 3k (real) resolution.