Mobile App Developer Needed

I'm seeking a skilled and experienced mobile app developer who is proficient in both iOS and Android platforms. The application is aimed at Russian speakers learning French. At a later stage, it could be developed for other languages. The general idea is as follows: the user subscribes to the application for a certain sum each month. Every day, via a push notification, they receive on their phone a sentence in French with the Russian translation, a recording of the French sentence (to ensure correct pronunciation), a few grammatical indications and colors to clearly identify which French word corresponds to which Russian word. The aim is to enrich vocabulary and grammar. The sentences in French and Russian as well as the recordings would be created by me. In detail: - Phrases are stored in the user's personal space, so they can be reviewed and replayed at any time. - Next to each phrase, there's a button for sharing the phrase and its translation, but not the recording (to listen to the recordings, you need to be a subscriber). - Users can download sentences in PDF format from their personal space, but recordings are not downloadable (to prevent users from sharing them). - To encourage users to stay subscribed, they receive gifts after a certain subscription period (for example, a gift after 3 months, then a few months later, etc.). A gift could be, for instance, a PDF file to print and cut out to make "flashcards" (cards with a French sentence on one side and the Russian translation on the other) - Users can subscribe for one month or commit to several months. They then benefit from a reduced rate. - A free 7-day trial is also available. There would be several subscription levels: - Level 1 Corresponds to what I described above. - Level 2 > Everything included in Level 1. In addition, the user receives a short test at the end of each week, with its answer key, to check their knowledge of the phrases they have received during the week. > The user can mark each phrase as "to review" or "learned". > Users have access to a "flashcard" mode: they see a phrase appear in Russian on their screen and have to remember the French translation (or the other way round). If they remember the translation, they swipe right; if not, left. Unremembered cards reappear in the future. There are other features I'd like to include in the application, but I'll talk about them privately. Please provide a brief of your relevant skills and previous projects in your bids.