Yes, it’s true that work should continue with Qt6 porting soon.
However, it would not have made sense not to release a Qt5/KF5 version first, as the porting work was pretty much done and anything that improves Qt5 experience is likely to help with Qt6, too. As 3.0 uses only single functionalities that are deprecated in Qt 5.15, the steps to Qt6 shouldn’t be that hard.