In KDE you can leverage Activities and Desktops, to provide exactly this
functionality.
It's simple to set up such rules - right click on the title bar, and
select Window or Application Settings. You can then match windows by
class or title (useful in Qubes), and set size, position, desktop
and Activity where the window will appear.
You can colour code each Activity, to match the colours used per
security domain, or have activities for different applications, as you
suggest.
Try it.