You can add an individual menu item to a page using the following shortcode:
[fdm-menu-item id="1"]
Where 1 is the ID of the menu item.
To use this shortcode on the page edit screen, just click the + button and add a new shortcode block to the page. Then write or paste in the above shortcode.
Attributes
The fdm-menu-item shortcode takes the following attribute:
id Accepts the ID of the desired menu item. Must be an integer.