Kafka has some things in common with where Sean Payton was in 2006.
Payton had only coached one Pro Bowl QB before Brees, Tony Romo. BUT Payton squeezed every drop of juice out of guys like Kerry Collins and Quincy Carter (and then later with Teddy Bridgewater).
Kafka, similarly, has only coached one Pro Bowl QB, Patrick Mahomes. But Kafka squeezed every drop out of guys like Daniel Jones, Tyrod Taylor, Tommy DeVito, and Drew Lock. Seriously, look at the jump Jones made in 2022 when Kafka came aboard -- I bet a lot of people don't remember that the Giants won a road playoff game that season:
https://en.wikipedia.org/wiki/Daniel_Jones_(American_football)#NFL_career_statistics
Kafka was still the Giants' OC in 2023. Jones battled through a neck injury in 2023 that sapped his arm strength and cost him three starts. Then he went on IR with a knee in November. Tyrod Taylor and Tommy Devito split the rest of the starts and did better than they had any right to expect (both with identical QBRs of 89 and a combined 13-6 TD-INT ratio).