Why are there 54 preferences files called AIRobin with version numbers following?

They are used as places to process background tasks. and one is created with every version/point version you have installed. Generally, these will be essentially be empty or with a few small pref files when not being used. You can safely delete any of them except for the verson(s) you are actually using or have installed. e.g. if you are currently on CC2026 v30.4 (AIRobin 30.4.0), you can delete any of the others. They will be recreated when needed anyway.