I recommend running your app with Double-length Pseudolanguage. It is a great way to stress-testing your app and see how adaptive it is and if your UI will hold to other languages that might be a bit more verbose or even with larger text sizes.
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Sometimes, with large font sizes, there's no other way around it but to offer an alternative layout. Small tweaks are often enough. Otherwise, the text will be barely readable. Larger text shouldn't mean less content or a worse experience. One thing you can do is to check if the preferred content size category of a view is an accessibility category. And, in that case, move things around to make room for the text, offer more lines of text, etc. https://developer.apple.com/documentation/uikit/uicontentsizecategory/isaccessibilitycategory
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.
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.
