I open Minecraft, and no sound is heard. I have the music pack, and I can tell when it works when the music plays. The sound only worked once since the millions of times I tried to hear sound.. I think it might be because Apple deprecated some audio in the coding, but that might not be the case. To reproduce, open Minecraft with the iOS and iPadOS public beta 4. I have a video, but it is 38.89 mb.

Edit: I have a(n annoying) fix. If you go into Multitasking after opening minecraft(note: Minecraft Main Menu should show) and open another application, then use Multitasking and switch back to Minecraft, you should have sound. Just a quick fix.