I have installed Kubuntu 20 on my Lenovo Yoga 920 and I noticed that the touch screen is not working correctly. For example, when I open Chromium and try to pinch to zoom, nothing happens. Also when touching the screen (one finger) the mouse cursor follows the finger (which is horrible to see as a mouse cursor should not be shown for touch events). I tried to boot up a live USB of Ubuntu 20 (with Gnome X11 session) and the touch screen there is working fine with Chromium pinch zoom correctly working and very smoothly and the mouse cursor problem isn't there.

Reproduced ON:
Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.4.0-39-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i5-8250U CPU @ 1.60GHz
Memory: 7.5 GiB of RAM