I am facing this issue too for a while and can't figure it out. Any pointers here?

I agree with that and was aware. Hence why I came to ask this question and see if there is any Apple framework I am not aware of, or an approach that fits. My first approach was indeed to use html & javascript but I am tending towards native to keep the experience the same across the app and because I won't have to "interop" between the JS world and native world for audio and midi calls. Thanks for confirming some assumptions though.