Hinting is bad with fractional scaling, Wayland and hintfull

I've updated Plasma to 6.0 and noticed this:

This happens with both QtQuick and QtWidgets applications and stops happening if I do any of the following:

• change system hinting settings from hintfull to hintslight
• set QT_QPA_PLATFORM=xcb
• set QT_SCALE_FACTOR=1.01 (the logic here is to make QHighDPiScaling::isActive() return true)
• set QT_WAYLAND_DISABLED_INTERFACES=wp_fractional_scale_manager_v1 (so applications scale to 2x instead of 1.25x)

My system scaling is 125% and it's systemsettings on the screenshot.

My guess is that those changes should apply on Wayland, too:
https://github.com/qt/qtbase/commit/0f7bc885aa7ae8cc3c448cc751aba4eba8c1c8b8
https://github.com/qt/qtbase/commit/7c506150a52031877145daceb032ccb882fd0a1b

They currently don't as Qt's coordinate system is equal to the windowing system coordinate system on Wayland and so QHighDpiScaling::isActive() returns false. Still, QPainter is scaled what apparently leads to such bad results. To make this logic work on Wayland, QHighDpiScaling::isActive() should be replaced with !qFuzzyCompare(QGuiApplication::devicePixelRatio(), qreal(1)).

Although it's just a guess, not sure whether it's the right fix.