Newly installed kicad 6 - no footprints (on WIN 10)

Uninstalling KiCad does not remove it’s configuration files.

As far as I know the github libraries have been deprecated for some years now.

Did you find this FAQ article:

In short:
Simply deleting (or renaming) the configuration directory fools KiCad into thinking it is a fresh install and it will then ask you if it should re-create the library tables. Make sure you do so.