I have the ix500 scanner and hooked it up to my new Mac with Catalina on January 19, 2020. Everything connected fine including wireless but when I tried to scan I got nowhere except a message having something to do with the folder it was to save the scans to.
I did not want to use the cloud app so I looked tirelessly and found the fix on the Fujitsu ScanSnap website. I uninstalled the driver I had, downloaded the most recent driver for the ix500 and Catalina OS, connected the scanner (including wirelessly), then followed the instructions included below and it worked first time I tried. Actually, I found it simpler then using the old ScanSnap Manager that was on my old computer.
Even though my scanner is not even 2 years old yet I know this model has been discontinued. It does work now with Catalina. It has to do with the extra layers of security in the current OS for Mac. See the steps below from ScanSnap website. With my system you only needed to check the box for ScanSnap Home (the others below it did not show):
