Just a small clarification: You are still "selbständig" (self-employed) if you do a "Gewerbe". The thing you don't get easily is a so called "Freiberuf", particularly if you don't have an engineering degree (though I managed to get it).
Tax wise it is actually almost easier to do non-EU business than doing business in Europe, because there are no VAT issues involved (and there are no tariffs on those things). You just invoice the net value.
Tax wise it is actually almost easier to do non-EU business than doing business in Europe, because there are no VAT issues involved (and there are no tariffs on those things). You just invoice the net value.