What major iPhone user problems are still genuinely unsolved?

Among the major problems iPhone users still face today, which ones do you think remain genuinely unsolved and could realistically be addressed by an independent developer?

If I were to build a prototype around one of those problems, what criteria would you use to judge whether it represents a genuinely meaningful solution?

Thank you for any perspective you’re able to share.

What major iPhone user problems are still genuinely unsolved?
 
 
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