In Plasma 5, the Desktop Grid effect had the ability to add and remove desktops with the "+" and "-" buttons. I think this behavior should be returned in Plasma 6.0. I'll explain why: in Plasma, in addition to the usual in-line desktops, there are also grid desktops, which are much more convenient to work with via Desktop Grid. However, there is no way to create or delete desktops in Desktop Grid, which makes it a bit difficult to work with. SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Neon (Unstable), Wayland KDE Plasma Version: 5.90.0 KDE Frameworks Version: 5.246.0 Qt Version: 6.6.0
Marking this as confirmed since this seems like a reasonable feature request.
Given that the Desktop Grid and Overview effects have been combined, I'm not sure how high of a priority this is anymore.