This implementation gets one thing most Metro clones miss, i.e the typography as structure paradigm. In Win8, there were no divider lines or heavy drop shadows to denote hierarchy. The hierarchy was defined strictly by the weight and size of the font.
We spent the last decade drifting back into glassmorphism and mica materials (win11) because people missed the comfort of texture but from a pure information density and rendering performance perspective - the flat, monochromatic 2D plane of windows 8 is a nice tangent. It removed the cognitive load of decoding the UI chrome for touch users.
ps: I'm impressed by the constraint of using native Qt/C++ here instead of taking the easy route with electron or QML/javascript bindings for everything.