Most of the most talented won't have those credentials and, in my opinion unlike getting sample problems, being asked for the credentials is such a red flag that the best won't apply.
I agree with that. The problem with third party certs which you allude to is they are almost exclusively taken by mediocre developers looking for an easy feather in their cap. Meanwhile true talent has no reason to bother with such nonsense.
The credential I look for when hiring is someone who has already done something remarkable.
The credential I look for when hiring is someone who has already done something remarkable.