I put most of the blame on the lack of a running game. I don't know if that's on the coaching staff for simply not even trying to run with the RB's, or they don't even try because they know they can't. Either way, it's a huge problem.
Very few offenses out there can be great with little to no running game. Their are outliers like Mahomes and the Chiefs, but that's one of those all-time talented offenses. The Bills are not that. These defenses are just teeing off on Allen. Most of the time when he has to eat it, there's nobody open. That's not really on him. Does a miss a pass here and there? Sure. But so does Mahomes and Brady.