FAQs are very useful if they really are FAQs like stackoverflow.

If there is some person "making up" FAQs it is rubbish. When CEO orders that "we need to make FAQ, make one" but no one is actually asking any questions that is the worst.

FAQ should be consisting of actual questions and then best would be each variation of way how people asked it to point to the right answer. Ideally FAQ should be curated by a person or first line support.

Synthetic FAQ is the same as documentation - someone writing things up and organizing it in a way they think. Ideal FAQ should help find question and answer that is already asked by someone else in a way that broadest possible audience would ask it.