Thank you! Can someone answer question 2 for me. That's what bothers me the most :/
That depends on where you live (Berlin), what nationality you are and to what bank you're withdrawing your Euro, I guess. If you want to be absolutely sure, ask a "Steuerberater (accountant) that specialized in Crypto or the "Finanzamt" (finance authority) directly. There are many things to consider and if you want to be absolutely sure, you need to ask a specialist.
PS: Welcome to Germany