Hmm. Using Arch in KDE X11 here:
The only sub-options I see under the Keyboard settings are “Keyboard” and “Shortcuts”. It’s likely that you have a package installed related to virtual and/or on-screen keyboards that causes this issue, or it could just be a Wayland-related issue.
Did you install the full KDE shebang (kde-meta), or just the DE (kde-desktop)?
6.6.4 doesn’t have the fix for the issue that kept resetting distro-overloaded settings. From this, related to what I wrote on Where are my displays? - #2 by stlnb.