On IOS, sound stops working altogether. If I exit the game and start an app with sound, then exit that app and go back to Minecraft the sounds in Minecraft start working again. This happens using AirPods or just the iPad speakers.   After a while, the sound stops playing again. Once I exit Minecraft and do anything else on the iPad I hear the system sounds (keyboard clicks,etc).  Back to Minecraft no sound at all. 

my version says 1.16.50 hotfix but your form says it doesn't exist.