Web audio in Phaser 3 not playing on iOS?

I've built a game using Phaser 3, and have implemented audio.

The game runs fine and sound plays beautifully on desktop browsers (Mac, Linux, and presumably Windows), as well as Android browsers.

However the game is effectively muted on iOS.

I've attempted the fix described here, by switching out web audio for HTML5 audio in the game config:

audio: {
  disableWebAudio: true
},

When I do this, audio plays but the game lags badly and the sounds don't mesh very well so I don't really consider this a solution.