Upvote:8
It is not a matter of being allowed to enter. The airline will not allow you to board the flight in the first place, not even your US-TR flight. You must reschedule or cancel your trip.
Airline personnel do rudimentary document checks before you board, using a database called Timatic, which states directly
Passengers are not allowed to enter.
except EU nationals.
As you know, EU and Schengen countries, of which Greece is both, have banned entry from third-country nationals effective July 1, 2020, except for diplomats and other extremely narrow categories. You have not stated your citizenship, but if you are not a citizen or permanent resident of an EU country, or a spouse or child thereof, the airline will not take any chances.
As it happens, Turkey has re-opened to tourism, and has some comparable geography, climate, and classical sites, so you might consider that.