Taking a loan allows you to receive the value gain in bitcoin during the entire term. You won't have to sell.

While that is certainly possible, you are exposed to currency risk if the loan needs to be returned. Additionally, and possibly worse, you might face a multi-jurisdiction legal case in the event of a dispute.

The custodian simplifies the transaction and assures safekeeping of the assets for capital providers. The improved transaction and safety facilities allows for competitive interest rates.

Getting a Germany IBAN is the first step.