Try restarting your iPhone. I know this sounds silly, but it works for me most of the time.

Same results in Xcode Version 15.3 (15E204a)

I hate to be correct, but as of 2024 developers can use Swift and SwiftUI to make macOS screensavers. I was able to confirm this technique works as documented here: https://digitalbunker.dev/creating-a-macos-screensaver-in-swiftui/ I’m posting because this thread came up in search results and I don’t want others getting the wrong idea about what’s possible.