Sunny Custom Webview

Hello, thanks
This last block worked, it helped to open an external URL

but when opened, the back button is not working, so how can we enable the return back to the previous webview?

Also i have one use case - the external link is whatsapp chat link - expected it when clicked on it - it should open Whatsapp - like happening on real website

webview is added to site
added whatsapp chat button icon to
when clicked on whatsapp icon - it opens -
on mobile it waits for second and automatically opens the whatsapp app

right now above last step is not happening