Although I have never done this, I do know the technical aspects of how this can be done.
What you'll need to do is use a VPN so that your IP address appears to be from a German location. Since everyone connects their Echo Dot using WiFi to their router, the router is going use whatever IP address that the ISP gives you. And if you're in the US, it'll be a US IP address. Nothing you can do about that. So you can't connect your Echo Dot to your router if you want to appear as a German IP address. That said, what you can do is set up a PC with software that makes it to have the functionality of a WiFi router. And with that PC, you will set up a VPN that exits to a German IP address. With all this set up, you would reset your Echo Dot and connect to the PC instead of your router.
Some caveats:
- VPN's are not free. You'll have to pay a fee to a VPN provider especially if you want an IP address from a specific country
- The PC that you'll set up with router software must be on 24 hours a day. It essentially will behave as a 2nd router that you'll use only with your Echo Dot. You could use it with other devices if you want those devices on a German IP address.
- VPN's are sometimes slow. Streaming music, videos, or even simple web browsing can have delays or buffering for several seconds.
- Even if you set everything up correctly and paid lots of money to do so, it might not work with the Echo Dot. Many VPN IP addresses are known and catalogued by large companies like Amazon, Google, etc. They might know that you're using a VPN and not allow connections with their servers.