Facebook slow over WiFi on Galaxy S6

[Alawishis]

Thanks for the suggestion to roll-back the WebView app. It corrected the issues that I was having (for now at least) and my browsing experience and apps are working much better when connected to WiFi.

I tried all of the suggestions except for the router changes with no success and I stumbled upon the issue. In my case it was an app called Clean Master. I noticed it was validating my application updates, something I didn't recall giving it permission to do . Uninstalled it all fixed. Hope this helps someone.