We may need to confirm your email if your Paypal email is different from your customer email.
Address matching is however not very likely to be the main cause of a transaction failure.
The fraud happens because it's an underground industry, it's an underground industry because of the puritanical values, etc.
That has nothing to do with Only Fans, though.
The chargeback process is usually manual meaning it requires non-negligible resources plus it impacts the fees the card cartel collects if the chargeback is accepted.
Ultimately it achieves nothing, as blind structure following without feeling for anything deeper than that within yourself is a soulless activity.
Porn is bad for business.
Every cardholder must follow these particular instructions to avoid getting their card declined.