This time quicker than every 2 weeks, but a new Plasma 6 ISO is up to publish some major changes.
This is a first ISO with Qt 6.6 (6.6.0RC), all of kf6, Plasma & KDE Apps were build from their latest git checkout 2 days on this new Qt version.
And this ISO includes Calamares QT6/kf6 based.
Not all modules are ready at this point, for example, none of the QML modules load yet, but using all widgets modules results in successful installs, so this ISO is now kf5 free.
Since it is not possible yet to run the bootloader choice module, only bootloader that will run on this ISO is systemd-boot, thus (legacy) BIOS installs will not get a bootloader.
For those older systems, either only use Live mode, or add the install to an already existing bootloader on your system.