We need up to 3 Java programs (1. Multiplatform audio player with special functions, 2. special picture viewer, 3. pro version)

Hello, we are a start-up from Germany and are searching for a coder to code two small programs for us. Our idea is that Java or JavaFX should be best suited for this project, but we could discuss other options. If this works well, there is also the possibility to code an extended Pro Version and to continue updating this project in the long run. This is an option only. What we need is someone who can provide different areas of expertise, starting from your coding capabilities while ensuring full functionality on all platforms (Windows, Linux, MacOS, iOS, Android) including the ability to add update and authentication functionality via key, as well as take care of the design. Two programs: 1. Audioplayer The main functionality of the player would consist of being able to play multiple audio files at once. 2. Picture Viewer This viewer would have to show multiple pictures at once. Sounds odd? If you're curious - write us! These two programs would need to be finished on all platforms by february 22nd. We estimate an overall workload of 20-40 hours.