International driving license still?

... I don't think that's accurate. Driving requirements are "harmonized" across the EU, and all EU countries must adhere to the same regulations regarding licenses (albeit each member state (=country) can have some particularities).

There have been no changes to EU regulations regarding licenses therefore if you come from a country which required Int'l Driving License when driving in the EU, that remains.

Check https://europa.eu/youreurope/citizens/vehicles/driving-licence/driving-licence-exchange-recognition/index_en.htm

I did check with the relevant authorities and also the renters
and the car companies and it was completely clear that it is fine for me to drive anywhere in Greece without the ITD

Here is another useful source, FAQs about international drivers permit put out by AutoEurope

https://www.autoeurope.com/international-driving-permit-faq/

Here is a link specific for Spain
https://www.autoeurope.com/international-driving-permit-spain/

The article I found stating IDPs were no longer required was directed at travelers from the UK after Brexit, not those from the U.S.

As mentioned in my initial response, the driving license regulations are harmonized across all EU countries. HOWEVER, as I also pointed out, each EU member-state might "add" its particularities (exceptions, etc).

In the case of Greece, as of June 2022, one of these exceptions is "if your driving license can be converted into a Greek driving license of a corresponding category" and this applies, among other to US-emitted driving licences. Source: Gov of Greece: https://www.gov.gr/en/sdg/vehicles/acquiring-and-renewing-driving-licence/driving-license-recognition-and-validity/non-eu-driving-licenses-exchange-recognition

In the case of Spain, as of Nov 2020, US-emitted driving licences ARE NOT recognized and an IDL is required. Source: DGT (Spanish Traffic Authority): https://www.dgt.es/nuestros-servicios/permisos-de-conducir/permisos-extranjeros-y-de-fuerzas-y-cuerpos-de-seguridad/permisos-validos-para-conducir-en-espana/

These questions are best checked at DIRECT SOURCES (=country's national authorities) and not in private intermediaries (ie. car rental companies). While the info provided by the latter should "match" the official one, it might not always be the case (ie recent changes in legislation, etc). Also, at the end of the day, the rules applied to you in case you're stopped will be those that the local authority holds as current, not what a private company website or even your own government website says.

It should perhaps be mentioned that the OP is Australian with that country's License.

How does all this apply to us who are not Americans (Australians, Canadians etc. etc.) ??

....Oh and don't read Spanish?