I notice that we have the option to move a window from one desktop to another or on all desktops. But is there a way to have it on 2 out of 3 or more for example? - or 3 out of 4 or more?
I also notice that if a window is set to appear on all desktops, I cannot use desktop grid to move with left click that window out from one of the desktops. A window can be there moved across desktops only if that window appears only on one desktop. Am I missing something there?
I don’t think there’s a way using keyoard shortcuts, however you can right click the title bar of any window (or alternatively press Alt+F3) and, in the “Desktops” submenu, select any desktops you want the window to appear on.
On X11 windows can only be on one or all desktops.
On Wayland windows can be on arbitrary desktops, like @firlaev-hans described.
Shortcuts can be used to send a window to a specific desktop. But I have omitted the fact that I’m in X11.
This is the first time I can identify a reason why I might need wayland 
(But the huge number of custom shortcuts I have is still keeping me back.)