Is there any shortcut for distraction-free mode?

Ctrl + ~ + 4 + 2

Ctrl + ~ + 4 allows you to exit/enter presentation mode, distraction mode, full screen

If you're using the default Mac shortcuts, you can use Ctrl+` 4 2.

Explanation:

Press and hold Ctrl, press `, release all; this brings up the Switch... menu. Press and release 4; this enters the View Mode menu. Press and release 2; this toggles Enter Distraction Free Mode/Exit Distraction Free Mode.

There is none assigned by default, but you can assign one yourself.

Go to Settings > Keymap and type distraction in the filter field (or expand the Main menu > View > Toggle Distraction Free mode tree). Right click the item and select Add Keyboard Shortcut.