Full Keyboard Access can be tested in the simulator! So convenient! You can enable it from Accessibility's settings in the simulator. And from there, you can navigate your app by just using your computer's keyboard.
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Grouping elements when it makes sense can make a huge impact on easing navigation with some assistive technologies like VoiceOver, Switch Control, or Full Keyboard Access. It also helps on reducing redundancy.
In addition to being able to test some accessibility options in the simulator using Environment Overrides. You can even preview some of these options before even running the app in the simulator with this Accessibility panel in Interface Builder.
You should convey important information in multiple modes, not just color. If you are still required to do so, at the very least you should complement that info with other modes, like symbols, if the user requested differentiation without color.
