I recently research on Android TV set top boxes from Pay TV and Telco Providers on their Android TV guide website. Where I found out that some Android TV devices even Google certified don't have Netflix or Prime Video Certification, some device have either Netflix or Prime Video only and some have both certification. I don't know why some other streaming apps like Disney Plus can support on all Android tv STB while Netflix and Prime Video need some permission to access to the device. Take for example my Sky Cable Evo box; it has Prime Video on it but not Netflix. Is there money involved here or is the industry practice to be more anti competitive?
FYI, Android TV devices from Pay TV providers are called "operator tier" devices in general.
Yes, all certified Android TV devices (operator tier or not) have to get additional certification from Netflix & Prime Video.
Netflix is more strict than Prime video when it comes to certification. There are very few devices that have Netflix support but not prime video.