For sanctioned countries, there is a very good chance to start successful Amazon alternaives as e.g. Digikala did in Iran ( https://en.wikipedia.org/wiki/Digikala ).

Anyway, other than crypto solutions (if supported), there is no way to have financial transactions with giant western companies like Amazon. Shipping items is also another issue.

Targeting local customers is easier. Then you can expand the business to the allies countries.