Did you try the solution presented here (I think the important is the flag to add to the build):
https ://devblogs.microsoft. com/xamarin/uiwebview-deprecation-xamarin-forms/
Go and see it to have screenshots as well.
The solution only involves three steps:
Use the right versions of Xamarin.Forms and Xamarin.iOS. Do you use Forms ≥ 4.5 and .Xamarin.iOS ≥ 13.10.0.17
Add a flag to the build configuration. (is it what you did with link all ?). Did you add the Additional mtouch arguments defined in the screen shot (--optimize=experimental-xforms-product-type)?
Build and submit your app to the App Store
On the Xamarin.Forms side we also had to make some changes to make all this work correctly. These new changes are part of Xamarin.Forms 4.5, including the pre-releases. Make sure that you are using the Forms 4.5 or newer NuGet package in your projects.
You also need to make sure that you are using Xamarin.iOS 13.10.0.17. You can check this from Visual Studio. This version of Xamarin.iOS is included with Visual Studio for Mac 8.4.1 and Visual Studio 16.4.3 and up.
With that in place, you can simply go to your iOS project, open the project properties and add this flag in the additional mtouch arguments field: --optimize=experimental-xforms-product-type this flag works together with the Linker Behavior set to SDK Only or All. If for any reason you see errors when setting the Linker Behavior to All, this is most likely a problem within the app code or a 3rd party library that is not linker safe. For more information on the linker, please refer to the docs.
If that works, don't forget to mark the correct answer, it may help others.
