There is a nuance I love to bring up: .NET biggest strength in the apps market today is the best support for native interop. Bridging .NET to Swift/Objective-C or .NET to (Android) Java. Every time there are layer in between, you loose. Either by loosing performance (your case) or by loosing capabilities (like the typical Cordova, React Native or Flutter Plugin).

Btw, work of Miguel de Icaza via the Xamarin acquisition.