Calling this "hijacking the Amazon app" is hyperbolic in my opinion. They replaced the shortcut in the app drawer. To me this looks like normal scummy OEM behaviour, like pre-installing spyware, "anti-" malware, adware etc. which sadly pretty much every mobile/computer manufacturer does.

Replacing the OS is one of the first things I do with every laptop, PC and mobile device to get rid of (most) crap that was installed without my consent.

and mobile device

Very little ability to do that with most devices these days, unfortunately.