Qt 6.0 Alpha was released two days ago. It is now making it's way into the KaOS repo. It will stay in kde-next only for the foreseeable future, since nothing can use it yet.
But it is time to get ready for the this move, KDE Framweorks should start to move to Qt 6 fairly soon, so better to get the build issues for a new major Qt out of the way now.
All Qt PKGBUILDs are converted to CMake right now, so quite a bit of work until all is done and working correctly.
https://kaosx.us/packages/packages.php?sortby=name&sortdir=&flagged=&page=&repo=kde-next&exact=&search=qt6

12 days later

So Qt6 will be coinstallable alongside Qt5 right?

Yes, and the beta is being build right now.

7 days later

Qt 6.0.0 beta2 is up.

It looks like Qt 3D will be available via Conan, is that the reason why it's still alpha in the repo?

In first look i think it will be like pip so it just build and install library. But it looks a bit more complicated.

a month later

All new to the KDE Apps/Release Services have now been added to [kde-next], including the all new Itinerary (including it's 2 new depends)