> But BV requires your primary place of business to be the Netherlands, which isn't always practical when you're trying to extend your activities internationally

You bill from the Netherlands and I think this is the only thing required. Uber in Europe charges your cards from Uber BV for example. And I think Uber is pretty international.

Especially as a solo entrepreneur, your llc would have to have substance in the Netherlands. Otherwise, it risks getting requalified as a country-where-you-reside llc.

Why would you otherwise voluntarily subject yourself to the extreme complexity of countries like Belgium or Germany if you could just set up a simple Bulgarian or Estonian llc?

It can be done, but there's contortions to sort out to fit a square peg in a round hole.

If someone has experience doing it right, I'd absolutely be willing to pay for their time to exchange advice.