You may want to talk to who-t or others if you have an interest in touchscreen calibration tools, or possibly try kde under x11: https://who-t.blogspot.com/2024/06/?m=0
Thanks - I'll see if I can find some tips there. Currently, I've got the screens rotated correctly (for me - both landscape) and the bottom screen recognises touches but in the wrong place and orientation. The standard KDE touchscreen and touchpad controls don't recognise that there's any device attached.