Some examples crash when running with Qt 6.5 kit

6.5 desktop kit isn't able to run many examples / demos from the welcome screen.
6.4 works fine.

Affected tried demos:
qmlsurface, texturesurface, opcuaviewer
Each shows the same crash, when trying to run the app.

12:23:16: Starting /home/william/Qt/Examples/Qt-6.5.0/opcua/build-opcuaviewer-Desktop_Qt_6_5_0_GCC_64bit-Debug/opcuaviewer...
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: offscreen, xcb, vnc, minimal, minimalegl, wayland, wayland-egl, vkkhrdisplay, linuxfb, eglfs.

12:23:16: /home/william/Qt/Examples/Qt-6.5.0/opcua/build-opcuaviewer-Desktop_Qt_6_5_0_GCC_64bit-Debug/opcuaviewer crashed.