SUMMARY Currently, KDE neon 5.18 LTS live/install images use synaptics by default instead of libinput, but ArcWiki says that "synaptics is no longer actively updated. If possible, use libinput" (https://wiki.archlinux.org/index.php/Touchpad_Synaptics). I believe that KDE neon 5.18 LTS live/install images should use libinput by default instead of synaptics. By the way, KDE neon 5.19 live/install images use libinput by default. SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE neon 5.18 User Edition LTS KDE Plasma Version: 5.18.5 KDE Frameworks Version: 5.71.0 Qt Version: 5.14.2
Pretty sure this will happen with the Ubuntu 20.04 rebase, right?
Fixed!