Its not surprising that you think PFF grade is the best stat. Not only is it completely subjective but it happens to be the only stat that supports your narrative.
I think QB rating is the best stat here. It might be a little crude compared to PFF but its not subjective at all and 9 times out of 10 the better QB has a higher QB rating.
We are absolutely arguing semantics. If I understand correctly you seem to think Ryan is currently somewhere around the 5th-6th best QB in the league, and I think he is somewhere around the 8th best... thats not really very far from each other.