In addition to the FrostCodes tips, I had a problem with WebView in AdMob.
I placed a privacy policy HTML file in the application that contains a link to my website's main page.
On the main page, there is a link to another page with YouTube videos.
On that page, if you click on the video, YouTube opens and displays an ad.
Google's robots followed all that path to find a problem, and because of that, I received a policy violation in AdMob.
I think AdMob's policy is more restrictive for web applications than for native applications.
Maybe is better to mix native functions with webview and check that the webview don't show ads in the pages with the ads in the app screen.