You cannot, unless you can convince the app developer to expand their distribution to your country. As you probably realize, it would not be an easy thing to change your country settings. Even if you didn't mind the subscription hassle, you might encounter other issues such as not having an accepted payment method which must be presented when changing country settings.
The support article Change your Apple Account country or region - Apple Support describes how to change your country setting on everything using your Apple Account, and the requirements and results of doing this.
Click on this link to learn how to contact an app developer - How to contact an app developer - Apple Support