I doubt that this is a KDE bug as much as a build problem, but perhaps someone can point me in the right direction here.

I just installed KDE using my distribution's repository, but it's an automated build and I'm pretty sure it's not tested. It will bring up Plasma just fine, but when I launch programs (Firefox, terminals, etc) Plasma does not reparent them. The windows are placed in the upper left corner of the screen; there is no control bar at the top and Plasma will not allow me to move or resize them. The applications respond to the mouse and keyboard fine, and the Plasma menus and other controls work correctly. It just doesn't reparent windows and they are all stuck in the upper left on top of each other.

Does anyone have a guess as to what might be misconfigured, and where I should start to track it down? I haven't used KDE in years. Thanks.

More detail: I'm working with the new Orange Pi 5 SBC, 8GB memory with 256GB NVME. It runs Gnome fine and seems quite fast enough to run KDE. I'm running an early Armbian distribution for this board, more or less Ubuntu-based. The kde-plasma-desktop package is "5:118ubuntu1".