I believe everything of mine in Creator is on whatever the defaults are. I do assume you are Linux and not Win/Mac? I will be on whatever Creator comes with Ubuntu 20.04 apt-get (unless I fetch it myself, I forget).
I assume by qtc you mean QtCreator?
QtCreator usually stores its settings in ~/.config/QtProject
So they actually are user specific.
Do you use same user account for different users?
And which settings do you change?