Hi! Based on what’s listed here - XDG Portal Pre-Authorization | Developer - I don’t know if the input devices side of that persistent permissions store has been implemented yet, perhaps just the remote desktop part?
For when it is - based on the man pages for flatpak-permission-set, the format of that command would be flatpak permission-set TABLE ID APP_ID [PERMISSION], where:
TABLEis the permission table being used (kde-authorizedin this case)IDis the name of the permission being granted - so instead of something like “vivaldi” or “steam”, it would likely have to be something like “input-devices”