yes we already had a macOS published on the App Store for 2 years written as a thin Swift app with WKWebView: https://apps.apple.com/us/app/waiterio-restaurant-pos-system...

https://developer.apple.com/documentation/webkit/wkwebview

The app store reviewers will allow apps with only webview only if you are offering some feature that would not be possible to implement in the browser alone.