It is sad that the application is only in English - I propose to translate.
I am ready to help in the translation into Russian.
(For example, you can use Weblate, or any other service. It is completely free for open source projects.)
Before we can even begin a translation, we would need to convert all the text in the app to use a localization framework. I have never done this on iOS before, so I would need someone else to work on that first.
It is sad that the application is only in English - I propose to translate. I am ready to help in the translation into Russian. (For example, you can use Weblate, or any other service. It is completely free for open source projects.)