Workspace switching with and without window is as you mention. Drag to left/right too. With 3.26 you can also drag the left/right split to arbitrary positions t

Workspace switching with and without window is as you mention. Drag to left/right too. With 3.26 you can also drag the left/right split to arbitrary positions that may be more beneficial to the task at hand. GNOME uses Super (Windows) by default instead of Alt for drag/resize. You can change it (and lots of other stuff) in the Tweaks application. Resize uses secondary click instead of middle I think, but also available in Tweaks.