Second window size state

I actually want a second window size:

fullscreen: not common but also possible f.e. for kiosk mode
fullsize: I don’t like anymore cause of borders off or only at the top and on the bottom like in dragon player
window size: I prefer window size for complete look
2. window size: but sometimes I want also a smaller window size f.e. when copying or using terminal

it would even not need a new button on the side when adding another button icon

// Is classic KDE coming back in future?