This is just a wish, but I want kde connect to be able to make toolbars for applications, based on the drop down menus withing the application, that you could control from the mobile device.
This is difficult to implement. AFAIK you can either tell an application to export its menu (make it available to the global menu widget or KDE Connect) or display it in the app itself. Both simultaneously is not possible. So this could only work in combination with some form of global menu.