I will continue using GTK until QT decides to stop being ugly (by default).
at the same time, vox doesn't really look like a lot of other QT apps (whereas a lot of modern GTK apps tend to have very similar designs).
notes seems like a great app. ux seems great from the demo reels. but it doesn't look quite as nice to me. the drop shadows (on click and drag) seem off. many things are very flat and wireframe looking. the icons look "cheap" (trashcan and slider/config particularly). i am unsure on how you choose between full black and dark grey in your design system but it feels a bit inconsistent.
all that said, i think the animations look great. very smooth.