SUMMARY
The output property of the window class is readonly https://invent.kde.org/plasma/kwin/-/blob/master/src/window.h#L109 . However there is a method to change this property on the workspacewrapper https://invent.kde.org/plasma/kwin/-/blob/master/src/scripting/workspace_wrapper.h?ref_type=heads#L370 it would be nicer if the api just allowed setting the output property on the window class instead of having to use this wrapper method.

Side note: this workspace wrapper still has a lot of "client" everywhere, whereas the rest of the code base seems to have shifted from "client" in KWin 5 to "window" in KWin 6 (at least from my experience from what I've seen). So for consistency purposes it would be nice to rename all references to client in this file to window as well.