Hi how are you im a very wellexperienced Fullstack Developer,
First of all, webviews on android are ok, and for iOS we now use WebKit, thats the newer "Webview" UIWebview is not supported anymore, but with WebKit all is ok
I can do this app for you in 1 day maybe 2.
Please let me know it would be a honor to help you out, you can also check my past works
Regards