Vega would replace the Fire OS that is installed on Fire TV sticks and televisions, Kindle Fire tablets, and other Amazon devices. This could simplify development for Fire devices alongside other React-ready platforms, including smartphones, desktops, and other smart TVs. Fire OS is a fork of Android based on the Android Open Source Project, but it’s far from the same thing. Amazon and Google struck a deal allowing for Fire TV manufacturers like TCL to continue making TVs with Android TV and Fire TV systems.

Source: Amazon Fire Tablets and other gear will reportedly switch away from Android

Very little of this plan makes real sense. It sounds like the Fire Phone or Windows Phone, neither of which worked out.