Musescore? Wireshark? Transmission? TeXStudio?
No-nonsense? Why does software have to be no-nonsense? I'd prefer for software to be beautiful.
People complaining about resources mean the limited resources of their computers usually. But it does lead to wasted natural resources by making hardware obsolete faster. And wasted financial resources. And slow and inconsistent interfaces waste cognitive resources.
No nonsense means functional. Not ugly.
> Find me a single successful QT based app.
And you've been provided a long list. Please don't move the goalpost.