Zoom both sides of the toolbar instead of the middle of the design screen?

Are you referring to the canvas area? Not sure if I'm getting it right.

If you're referring to the zoom in the canvas areas, it depends on how you're applying the zoom. Is it using the keys Ctrl (+/-) or the mouse/trackpad? To zoom in specifically to a part of the screen, you need to use the mouse cursor, hover the area you want, and then scroll the mouse. But using the keyboard shortcuts, you cannot get this result, you need to use the mouse pointer/scroll..