Once the full site has loaded, avoid tapping on the Facebook logo on the top-left corner and also avoid tapping on YOUR profile name because if you do it will detect that you’re on a mobile browser and direct you to the web app (touch.facebook.com) On my iPhone the full site works very fast, just like a normal computer.
https://antranik.org/how-to-load-the-actual-full-facebook-site-on-your-phone/

