Navi was a thing before even PS4, why people keep spouting BS I do not know. All Cerny does, as anyone would do in any comparable position was work with AMD to fit their needs.
Sure most likely. Im sure the version that sprouted from the sony colab is more suitable for console gaming maybe some extra feature that is beneficial for gaming only or something pc uses for other things that is unnecessary for gaming that was left out making it cheaper. Cant say that I know. But from the sound off things they have been at it for a while and yet no word or even rumors from MS if they had any special work done.
It takes genuine talent to see greatness in yourself despite your absence of genuine talent.