I loved and even flexed how I can use multiple mice and keyboards together in Gnome X11 with the
xinput create-master [name] and
xinput reattach [slave device name or id] [master device name or id] commands.
Making you able to use two mice with each having its own Keyboard focus. This was never or partly possible with a bug in Plasma 5 X11 as the Mouse Cursor did fight with the location.
Its still kind of possible now in Wayland by having a Wacom Tablet and a Mouse, which automatically creates a custom cursor for the Tablet, but it still fights in Plasma 5 Wayland for the position like it does with Plasma 5 X11 custom xinput setup. In Gnome not which shows that the feature should be possible.
It would be great if it would be possible to set any Mouse as a new custom Cursor with each having its own Keyboard focus (to set) like it was possible with Xinput.
Especially for Plasma 6 I can imagine this as a very great feature for being more productive on the same PC or better teaching by using a second input and the application twice next to each other.