Create a Flutter recording app

I need to develop front and backend of a very simple project. It is a recording app, with the possibility to cancel and modify (actually overwrite the recording). The recording will have a max time of 15 sec, with a delay of 6 seconds with a vocal countdown, when you press the recording (the recordings are called routines), and will loop for 5 times with the same 6 seconds delay. I have an idea of how it'll developed (frontend) and it'll be attached here. I need only freelancers with macbooks to develop the app, since i need to see the final result on iPhone, but the app is for iPhone and Android. The budget is around 50€ since is a very simpe app.

Happy bidding!!