I just turned in our rental to Hertz in Piraeus. (Port of Athens) we bought the Amex insurance.
They still put 1000euro on the card as “just in case” on returning the car, they have a perfunctory glance and returned my deposit.
Very easy going and not at all stressful.
I have done rental returns In France and the woman accused me of not filling up the car.
She wouldnt come out from behind the desk…. It was strange indeed.