Saints candidates Kellen Moore, Joe Brady [and Kliff Kingsbury] compared to Ben Johnson in offensive rankings

And the 2022 Bills were #1 in red zone efficiency, and then #4 in 2023. In the first 10 games of 2023 with Ken Dorsey, they were #2 in red zone efficiency, but were #16 the last seven games of the season.

I think the red zone efficiency is correlating with something else, and it isn't Brady.
Actually, as @DSnfla pointed out, Teddy B called out the fact that the red zone was something they didn't emphasize. Also, if you believe that red zone efficiency is tied to Josh Allen, they would have maintained their efficiency last season. Brady basically had to call Dorsey's offense. Josh Allen got worst with Brady last season but this season, he implemented his offense and here we are.