How does hijacking on Amazon work?

Hi all, I am trying to get into selling on amazon, but one thing that has me really confused and hesitant about whether to sell as branded or unbranded is hijackers.

So, for all unbranded products, is it basically a given that the listing will be very easy for anyone to hijack? Could you just put your company name in the listing and in the photos, but sell the product itself as unbranded (i.e no logo on packaging)? Wouldn’t this prevent or at least deter hijackers? Would they be able to tell it is actually generic? Is this against terms of service? If your product is unbranded, and it gets hijacked, is there anything you can do to remove those hijackers? How is it even possible for a listing to be hijacked? Since, when you sell a product, it is assigned an FNSKU (which is unique to yourself). So, if someone were to try and sell the same product, wouldn’t it have a different FNSKU? Thus amazon would know they are different products. Where exactly does the brand have to be for branded products? Is it fine to just have it on the cardboard box? Or does the individual items themselves have to have a brand/logo on them? Or is just having it on the packaging enough (i.e the plastic bag the item is in).

Ideally, I would like to sell my products without branding on them (for cheaper manufacturing), but still put my company in the listing & photos in order to build brand reputation. And later on, simply ship products do have branding on them under the same listing. (but as I understand it, is it incredibly hard to switch a listing from “generic” to “branded”? And I would have to start off as generic).

Thank you in advance for any help!