I use it on KDE Neon without major problem (but with limitation) for the most part
But …
For you’re 1st point I plug my 2in1 laptop so don’t know
What settings menu?
3-4 point it look like problem you could encounter with X programs.
Are-you on X? Maliit is for a wayland environment.
if you’re on a wayland session, on what program do you encounter this? The problem with the wrong input I encounter this in Chromium wich was running in Xwayland (not wayland then).
You can verify if youre program is running with Xwayland with