There is another accessibility trait: .playsSound, that does a similar thing than .startsMediaSession. This one seems more suitable for buttons that have their own sound effects when interacting with them, like it often happens in games.
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When interacting with a button with VoiceOver, the accessibility label is repeated to the user. If you are playing some audio, it could be difficult to listen to it properly. To avoid that, you can add the .startsMediaSession accessibility trait.
You can add an observer to listen for changes in the content size category, in case it is more convenient than overriding traitCollectionDidChange(_:).
Support both orientations, if possible. I know not even iOS itself does it, but it hasn't always been like that. You'll create a more robust UI that will be easier to port to iPadOS. And especially, don't force your users to rotate their devices.
