I have a few Qt apps and haven’t observed anything like this; most likely that’s been fixed. I’ve been using Wayland since April.
(One thing that is comically broken about Sway and I think Wayland in general is cursor sizes. Specifying `seat seat0 xcursor_theme Adwaita 96` nets me at least four or I think five different cursor sizes, varying by app, and at least one of the dodgy sizes is actually a fractional scaling bug, scaling by ceil(1.5) rather than 1.5.)
