The Scene gizmo is an axis navigation tool, generally docked to the top right of the Scene view window.
- Click the center—or the label below the gizmo—to toggle between Perspective and Orthographic views.
- Orthographic perspectives flatten object distance, switch to perspective if unintentional.
- Each axis arm can be clicked on to realign the view to that axis.
- Rotation lock can be toggled via the lock icon to the top right.

Using the tools mentioned above you can fix most rotation issues with the Scene view.
I still have issues with the Scene view.
I can't find the Scene gizmo.