I am of the thought that extracting honey from supers above an excluder from hives healthy enough to fill supers above an excluder, makes for minimal AFB exposure. Now extracting honey from dead hive brood chambers would certainly increase the chances of AFB exposure. I have been extracting multiple persons honey on my same equipment since 1976 with no extracting attributable AFB in that 48 year period.
I have in that time frame had hives in the field get AFB. Was it due to extracting contamination? I doubt it.
All of my opinions and suggestions are based on my five decades of actual beekeeping,
not so much on book learning, watching YouTube videos nor reading internet sites.