Hello, and thanks; this must be perplexing.
I think the KYC team is for some unknown reason convinced that the current ID "does not clearly display all key personal identifiers required for verification in a format our team can process, including your full name, surname, and date of birth." Maybe the situation stands in a bit of a different light. Follow my thoughts, please. In order to pass the KYC, the casino needs you to provide concrete details in the form of an official document, thats normal, but if the ID does not provide those details (I'm not saying it does not), it makes sense they asked you to provide an alternative document instead. Maybe it's not about why they do not accept the Greek government issue ID but whether it provides details expected from such a document.
I do not know the answer, but if you're saying that at the same time Greece is currently in the process of transitioning from the old-type identity cards to the new format, perhaps it plays a role too and since this casino is an offshore casino, they may not be familiar with this fact at all.
I would say it's imperative to finish the KYC even so by sharing other documents and be done with the process. So, even though I imagine the outcome was an unexpected turn of events, your willingness to cooperate is worth appreciation. I hope the new ID will resolve this situation!
Automatic translation: