If someone still need it. I solved it by following the next steps:
- Get any machine running MacOS (it would be easier if you have at least Mac Mini) - install XCode. 1a) IT IS IMPORTANT! Launch a dummy project on XCode. 2). Install Visual Studio 2019 on Mac. 3!!) If you are planning to develop your Xamarin project on PC then you also need to get PC. If not, just use Mac
- Install VS 2019 on PC and create Xamarin app. Launch it.
- Copy your Xamarin app on Mac and open on Visual Studio
- NOW, try to change your icons in Info.plist. (App icon and Loading screen). You must be asked to open the XCode for editing.