There is an accessibility trait for defining something that represents a custom keyboard's key: .keyboardKey. It allows VoiceOver users to change the typing mode to Direct touch typing. The calculator app or an access pin pad, are some examples.

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When using VoiceOver on a device without a home button it can first be confusing how you can do a few things, including going to Home from an app, or opening the App Switcher, Control Center, or Notifications. Here's a quick guide for you.
If, for some reason, you are creating a button from scratch, instead of relying on UIButton (perhaps you are adding a fancy micro interaction animation?), take into account that you’ll need to configure the button accessibility trait.

Sometimes your UI will just not scale for large text sizes. Simple changes, for large sizes, like disposing elements vertically instead of horizontally, reducing the number of columns, and allowing more lines of text, can do the trick most times.