Where did you see this one??
Short answer:
Company will have permanent establishment in Estonia and is a tax resident in Estonia. Greece is the place that he lives. That's exactly the case of 'e-resident'.
Long answer:
Estonia has a simple rule which says that a company is a tax resident in Estonia if it is incorporated under Estonian laws. If you have registered your Estonian OÜ, then this means your company is an Estonian tax resident and subject to tax in Estonia.
However, some countries have different rules for deciding if a company is tax resident. It is common that in addition to the place of incorporation, the place of effective management triggers tax residence. If you run your company from a country with such rules, then the company might end up having dual tax residence – this happens when two states believe that the company is tax resident in their jurisdiction and will want to tax the company’s profits.
In case business activities of this company are carried out elsewhere or the company is managed from outside of Estonia, the income received in a foreign state will be taxed in this foreign state and Estonia will ensure avoidance of double taxation.
From a personal experience, as I live in Greece as well, if activity of your company is software development services or consulting or other digital services and many other, is a tax resident in Estonia.