At Qt6 all(?) enumerated types have been moved from from a "general, high-level" class/namespace --- like Qt::AlignLeft or QVideoFrame::WriteOnly --- down into a more "specific, low-level" class/namespace --- like Qt::AlignmentFlag::AlignLeft or QVideoFrame::MapMode::WriteOnly. You need to change all your code accordingly. There isn't a definitive list, you just have to find out and do it as necessary.
In https://stackoverflow.com/questions/72086632/migrating-to-qt6-pyqt6-what-are-all-the-deprecated-short-form-names-in-qt5 and/or https://pypi.org/project/PyQtEnumConverter/ somebody wrote some kind of converter for Python/PyQt6 for this, maybe it will give you inspiration to understand what has changed.