Not a complete answer, but I stand behind Privacy Browser. The dev has a great blog explaining how the browser works:
https://www.stoutner.com/webview/
https://www.stoutner.com/privacy-browser-android/core-privacy-principles/
https://www.stoutner.com/privacy-browser-android/permissions/
I appreciate the transparency of the Dev and I am looking forward to the long-teased 4.x series that will ship with its own webview.
If you decide not to use it, keep it on your watchlist.