Jest with TypeScript spies and mockImplementation with a React Component

I'm trying to implement a partially mocked WebView for testing in React Native. I have tried to setup a spy on the WebView component only overriding the injectedJavaScript prop. I would have assumed this works:

import WebView, * as RNWebView from 'react-native-webview';

// keep all props from the WebView componen, but override the injectedJavaScript prop
jest
  .spyOn(RNWebView, 'WebView')
  .mockImplementation(
    (props: IOSWebViewProps & AndroidWebViewProps, context: any) => {
      return (
        <WebView
          {...props}
          injectedJavaScript={`window.ReactNativeWebView.postMessage("CUSTOM_MESSAGE")`}
        />
      );
    },
  );

But I get the type error:

Argument of type '(props: IOSWebViewProps & AndroidWebViewProps, context: any) => JSX.Element' is not assignable to parameter of type '(props: IOSWebViewProps & AndroidWebViewProps, context: any) => WebView<unknown>'.
  Type 'ReactElement<any, any>' is missing the following properties from type 'WebView<unknown>': goBack, goForward, reload, stopLoading, and 9 more.ts(2345)

I don't get it. How is the <WebView> I am returning being recognized only as type ReactElement<any, any>. Shouldn't <WebView>'s type quite literally be WebView? Really lost here, not sure why TypeScript is complaining. If I add as any to the end of the return statement, TypeScript is satisfied:

jest
  .spyOn(RNWebView, 'WebView')
  .mockImplementation(
    (props: IOSWebViewProps & AndroidWebViewProps, context: any) => {
      return (
        <WebView
          {...props}
          injectedJavaScript={`window.ReactNativeWebView.postMessage("CUSTOM_MESSAGE")`}
        />
      ) as any;
    },
  );

But this is a hack and I want to know why my mock types are not being understood by TypeScript.