Accuracy rarely gets better. Good coaching can mask accuracy issues by scheming receivers open and allowing easy reads that build confidence early in games. This is what we've seen with Josh Allen...he isn't any more precise with the ball than he was as a rookie...he just runs an offense geared to mask his shortcomings and highlight his strengths. We see similar things with other QBs with good coaching staffs...Baltimore being the most obvious.
This staff has one game-plan and it has nothing to do with helping the QB. To the contrary, it's dependent on having a QB that can bail you out of consistently bad down and distance...behind a line built to run block.
That was some legitimately nuanced individual work, using the left hand when they are won't be within 3 yards of Tua before he gets the ball to Tyreek.