Tabto move between the left side (General, Account, Shortcuts) and the right side. By clicking the Up/Down arrows you can navigate each side.
When focus is on a toggle setting you can click Spacebar/Enter to turn it on/off.
When focus is on a shortcut setting you can navigate the buttons with Left/Right arrows.
You can minimize the settings page with
Ctrl + M and close it with Esc . You can quit the app with
Ctrl + Q and then Enter.