Is that much of a problem for a catalyst? Presumably you do not need many of these: at water treatment plants and at the waste-stream for manufacturing processes which emit PFAS. You might not be able to justify the expense inside your home water purification system, but it could still be cost effective for large scale installations.

Activated carbon filtering removes up to about 75% of PFAS. Reverse-osmosis removes almost all.

Doesn't get rid of them, to be clear. It would still be better if a way could be found to chemically (and cheaply) convert them to something less harmful.