Generally, for cross-platform UI classes, we use handlers for handling on MAUI, please refer to Handlers.
FlyoutPage, its corresponding handler is
However, in my tests, I found that setting the width still doesn't work for Android and Windows platforms, and MAUI hasn't implemented this handler for iOS. Here is the source code: FlyoutViewHandler.iOS.cs.
Therefore, it is more recommended to post your issue on GitHub to make our product group aware of it, or use
Shell.Flyout to implement this feature.
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