Check isReduceTransparencyEnabled to lower transparency. A great example is Spotlight. Not only transparency is removed but it keeps the main color of the background, it feels personalized and contextual but reduces noise and improves contrast.
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Touch target sizes are recommended to be at least 44 x 44 points. Buttons in the navigation bar ( especially when not using nav bar button items), dismiss buttons, and custom toolbars, are use cases that tend to have smaller sizes.

@azzoor is the developer of the Braille Scanner It uses computer vision to locate the page and Machine Learning to match Braille to letters. You can see English letters above the braille, convert them to speech, copy and paste it... so cool!

Configuring the header accessibility trait, when appropriate, is one of my favourite accessibility quick wins. In this example, you need a single swipe down, instead of 12 swipes to the right to get to from Podcasts to Artists, in the app.
Content © Daniel Devesa Derksen-Staats — Accessibility up to 11!