@endurojunky I am glad you got it to work. :)
I couldn't get my RFID unit working in the beginning too, so I used an Android app for testing. That app tells you what keys it used to access the individual sectors. I then google for rfid default keys and found the link I mentioned. The UIFlow block doesn't allow to change the keys, so I looked at the source code of UIFlow. That source unfortunately wasn't update for two years, but the RFID unit is in there. There I found the default key being used: https://github.com/m5stack/UIFlow-Code/blob/master/units/_rfid.py#L284. This also helped me to find out how to set the keys.