I was using Xrandr to create an extra virtual monitor from an unused video interface

The problem in KDE is that, it creates a partially usable monitor, which doesn't work many things:

It doesnt appear in KDE Display settings as an extra display
The contextual menus appear in the main display, never in the extra display created by xrandr
The bars and widgets doesn't work as if it was an actual monitor
No wallpaper obviously, the background is black
It feels like if KDE doesn't see it as a display, but some random area that has popped out of the blue.

I'm using this extra display/monitor, instead of using those Dummy HDMI devices, so I can play with deskreen and have another device like a tablet as a secondary screen.

Any ideas on how to improve this situation?

PS (just in case): The point here is not using the dummy plug because I don't have unlimited ports in my laptop, and in this case I want to plug-in multiple tablets or screened devices apart from the "extra one" that comes from the dummy plug. Also sometimes the only port available is occupied by a RJ45 connector, so it's a pain to waste that port just because of using a dummy adapter for this stunt

Strange that something that can be easily achieved in Gnome cannot be done with KDE.

Maybe there is a better alternative to XRANDR in KDE?