Here is some good quality Greek olive oil available in US, reasonably priced, that you can buy without fear of adulteration or other shadiness:
https://www.amazon.com/Terra-Creta-Kolymvari-Protective-Desi...
https://www.amazon.com/Iliada-Extra-Virgin-Olive-Liter/dp/B0...
The Greek extra virgin olive oil sold at Trader Joe's is also very good.
Avoid the - Whole Foods & 365 branded - Greek EVOO at Whole Foods: it was rancid every single time I've tried it.
[1] https://www.reuters.com/article/us-italy-crime-food/italian-...
[2] https://www.oliveoiltimes.com/olive-oil-basics/mafia-olive-o...
[3] https://www.forbes.com/sites/ceciliarodriguez/2016/02/10/the...