Do your 2 monitors use different scaling?
You might want to take a peak at these bug reports to see if any match your situation:
https://bugreports.qt.io/browse/QTBUG-112911
https://bugreports.qt.io/browse/QTBUG-102356
https://bugreports.qt.io/browse/QTBUG-102982
https://bugreports.qt.io/browse/QTBUG-101947
If you find one, please let me know and I can check if a fix is already in Qt 6.5.2 or not.