Yes, but it’s less common to have completely unknown effects and from the perspective of pollution they have the desirable property of being broken down quickly when discarded or if bits flake off during normal use. That still doesn’t mean you can’t overload the ecosystem but it does mean that problems can self-correct more.
The natural/synthetic distinction is arbitrary, but you are both right.
The correct approach would be to get more granular and specify that we only want to elininate chemicals, whether natural or synthetic, that do not break down or are toxic.
If you find a natural source of PFAS ("forever chemicals") then it isn't any better.
