The problem sadly is Wayland. While wayland generally improves touch input, Xournalpp has those hiccups & glitches, for the ones are know are actually GTK bugs.

The problem sadly is Wayland. While wayland generally improves touch input, Xournalpp has those hiccups & glitches, for the ones are know are actually GTK bugs. I'm still sticking with Wayland though. I used Xournalpp one year before I switched on Xorg.