Not so many, really
There really aren't very many cameras sold on Amazon. Most of them are the same handful of cameras rebranded over and and over. Even companies that you'd expect to actually make cameras are sticking their label on something else.
This turned out to be extremely frustrating when I was looking for a security camera. Those few cameras have completely garbage firmware running under a patchwork of open source Linux software that somebody likely found on a sketchy FTP site 10 years ago. I'd open the box of a brand new camera and realize it was the same as the old camera. Default login won't stay off, pages not checking authentication, and much easier to crash than to keep running. I eventually started asking companies to send me sample videos so I could compare headers.
I'm guessing that TRENDnet was the vendor that said they have no idea what to do. Their TV-IP310PI is a defective Hikvision camera that they can't support. Other models may be similar.