android - Nativescript WebView on Android API 30 yields ERR_ACCESS_DENIED

Question

I have a NativeScript 6.8 JavaScript app that uses WebView to display an html string composed within the app that references local image files. The Google Play Store is forcing me to support API 30, and when I do, the WebView fails with

net::ERR_ACCESS_DENIED(-1)

I found this post that suggests I modify some of the Android WebView's access settings, such that my code now looks like this

AndroidManifest.xml:

<application 
  ...
  android:usesCleartextTraffic="true">

xml:

<GridLayout>  
  <WebView id="annbyday" loadFinished="onLoadFinished" src="{{ htmlsrcForDay }}" />
</GridLayout>

js:

exports.onLoadFinished = function (args) {

  if (args.object.android) {
    if (!args.error) {
      let webView = args.object.android;
      webView.getSettings().setAllowFileAccess(true);
      webView.getSettings().setAllowContentAccess(true);
      console.log("announce-page.onLoadFinished:  settings set");
    } else {
      console.warn("announce-page.onLoadFinished:  " + args.error);
    }
  }
}

When I run this, I get these messages in the console:

JS: announce-page.onLoadFinished:  settings set
JS: announce-page.onLoadFinished:  net::ERR_ACCESS_DENIED(-1)
JS: announce-page.onLoadFinished:  net::ERR_ACCESS_DENIED(-1)
JS: announce-page.onLoadFinished:  settings set

On first navigation to the page the android error screens displayed. But, if I re-navigate to the page I get just the "settings set" messages and the html displays correctly. It's as if the settings work, but they're not being set soon enough. Moving the code to the LoadStarted event has no effect.

I feel like I'm close; I welcome any help.