Do I need to close my Amazon account if I stop selling in Germany?

Closing your Amazon account is not necessary for deactivating your VAT number, as long as you no longer have inventory in Germany.

You don’t need to fully close your Amazon account to have your VAT number deactivated. The key requirement is that you no longer have inventory in Germany. As long as that’s the case, you can continue selling in other countries without needing to close your account.