Recently I was testing an IOS app on my wifes phone. The UI was completly broken. Turns out she had dark mode enabled. That led me down the path of adding dark mode support to the app. Which is testable via the Xcode simulator if you know how to enable it.

Command + Shift + A: Toggles dark mode

source: https://www.kindacode.com/article/how-to-toggle-dark-mode-on-ios-simulator/