That is by design. It separates the payment processor so it does just that, just payments. It is like money, once you give it to someone else there is no automatic way to fish it back from their pocket to yours. The correct avenue to deal with fraud, bankruptcy and other malicious actor is the small claims court (or civil court, or criminal court).
The moment you start burdening the payment processor with the roles of judge/referee over all goods and services you end up with the mess we have with CCs where Visa/Mastercard are morality czars that dictate what goods and services are valid or invalid, nuking people and companies out of modern society for their own arbitrary reasons.
Edit: And just to add, you can have "chargeback" for PIX as a separate service, most banks offer PIX insurance that is basically CC chargeback by a different name. But the key is that it is separate from the payment infrastructure itself, it is an insurance service that you contract separately. And that separation ins very important, the insurance company can't roll back transactions arbitrarily, or deny people access to the financial system, they have to pay the victim and then claw back their money in court, which is the appropriate venue to decide who is right or wrong in a transaction.