Unfortunately we have not added QT6 to our BSP yet and QT does not support Yocto-dunfell so you are in a bit of a bind here. I don’t see anything obvious in the error report that would get it to build for you. Is there a reason you need QT6 with Dunfell? Our next BSP is planned to be on the next Yocto LTS which should be in sync with the QT releases.
As I am starting the UI I want to start development in Qt6 such that I don’t have worry about changing my code later. Also Qt6 has some feature/bug fixes that we need.