Well I have some idea's maybe.

If you didn't uninstall your video card drivers after you upgraded that could be the problem, because you need windows 10 video card drivers for your graphics card.
Are you running DX11 on FFXIV try shutting it off and using DX9 instead maybe that could be the issue.

Uninstall browsers and FFXIV reinstall browser first then FFXIV after.

Try going to CMD admin and SFC /Scannow let it run see if you have another issue that it will repair, let it run.

Other than that, I would backup all your stuff then do a fresh install of everything if nothing works.

Would be best form of action if none of these things work.