Region change

You can try contacting the developer and see if they will extend the country distribution of their app. Click on this link to discover 'How to contact an app developer' - https://support.apple.com/HT207959

Not easily. For example, do you have a credit card billed to you at an address in Germany?*

This article describes how to change your country setting and the requirements and results of doing this:

Read how to "Change your Apple ID country or region" click here --> https://support.apple.com/HT201389

*From: Payment methods that you can use with your Apple ID; click here --> https://support.apple.com/HT202631

"Make sure that the billing address for your payment method matches the billing address for your Apple ID. In some cases, you might need to call your bank or financial institution to authorize international or online purchases. You might also need to confirm that the mobile number associated with your payment method is correct."