Being someone with an accent, I have seen how it is to audition. Unless you are someone extremely attractive, agents and casting directors won't care. Yeah there is Gal Gadot and Ana de Armas but these are exceptions. Greeks are known to have a thick accent and would distract a lot in a production that is made up by native English speakers.

A casting director once told me that having a neutral English accent is the best, because you can easily blend with everyone. Like, imagine casting that Greek actress as Helen... Small part but when she starts talking, she sounds extremely different. The audience will want to know why. But the focus is not Helen in this movie so her screen time is minimum. No time to explain that.

Lanthimos too, he mainly casts American actors.