Every addon has been turned off and the issue still remains. Therefore it is your problem still.
Every addon was disabled. older versions of Shadowed unit frames were installed and the issue remained. And considering its from multiple sources and the third party addon thats broken for her is not broken for myself it can't be that.
So the least you could do is at least look into the issue instead of just brushing it off.
When i'm telling you that with every single addon except shadowed turned on that the config menu can't be accessed then it is no way shape or form a third party add on issue aside from your own. aside from that shadowed unit frames no longer appears in the interface add on list at all in game.
We've completely done a hard reinstall of SUF and still gotten nothing. When you first log in it will give you the option to unlink/link your frames but still no config window.