After seeing Phoronix's post that the KDE team is interested in finding essential bug fixes for new users that usually get overlooked I came here to help out. I own a OneXPlayer which is a handheld like the Steam Deck with a Touchscreen so I'll be making a ton of reports that will probably translate directly to Steam Deck users.

That being said the first thing I ran into was while changing my screen orientation (Handhelds screens are not landscape, instead they are portrait right displays) the touch input got inverted and the top left was bottom left etc. Wayland didn't appear to be effected by this.

That being said out of the box I think KDE should have a proper touch solution that hides the cursor when touch is detected instead of acting more like a trackpad keeping the cursor visible.