Thank you for contacting Intel Community. Generally, the device part number ended with the additional suffix 'AB' is referring to customer-specific ordering suffix, the material that builds directly for some specific customer request. These are added to the device part number when a device has undergone additional qualification upon request.
Unfortunately, since the APEX 20K device families were obsolete since 2017 according to PDN1619.
There are limited support on the obsolete part.