omarchy/hyprland is the first compositor-native implementation for cua-driver, but the goal is a portable contract.
the key pieces are isolated synthetic cursors, target-window routing, and input delivery; KDE would need its own compositor integration to implement that cleanly though! that is a direction we're exploring next
I run a Debian KDE box too, so I am curious about this one. The compositor hook sounds like the hard part, but a portable path would be huge for anyone not on Omarchy. Curious whether the same cursor plumbing can land cleanly without replacing the desktop.