Cultural and/or musical concerts in Athens? Elsewhere?

I suspect scheduling for events in the fall is not finalized yet so that may explain why there
are no announcements. But the Athens and Epidaurus Festival should include events at
the Odeon in Athens and the ancient Theatre of Epidaurus, which, in my opinion, would be
very neat places to see a performance (but bring a seat cushion).

Too early for events in September.

Check:

Athens:

https://www.thisisathens.org/ (page: What's on)

https://www.opanda.gr/ (in Greek)

Epidaurus Festival: https://aefestival.gr/venues/?lang=en

Naxos: https://naxospress.gr/ (in Greek)

Kalambaka: https://www.kalabakacity.gr/category/ekdhloseis-events/ (in Greek)

If you like folkloric performances you may want to check out Dora Stratou Dance theatre -- in existence 60 years, showcasing tradtional dances & costumes from all over Greece

A Google re schedule only produced this info for 2024, but shows that perfomances normally run until late September
https://www.grdance.org/en/performances/

Here's a YouTube video - showing the great variety of costuming...https://www.youtube.com/watch?v=NwZNAMkF6a0
Most years I visited Greece, its season hadn't opened... but I finally managed in Late May -- open-air theatre, 90 minutes of nonstop traditional dances, all kinds of regional dress. Two tips • Mosquito lotion handy and • you can easily walk to theatre through a park, from the no-cars promenade S of Acropolis, but afterwards, NO cruising cab nearby, so arrange before hand for taxi pickup in parking lot.

In Athens, we attended "Medea and OtherFriends I Made in Athens"
Its in English, it's an introduction to Ancient Greek Theatre and its funny.

https://www.koilon.gr

Its not high brow stuff and it's not folkloric, so research it, to see if interests you.
We enjoyed it a lot.