By default, modals that are added to pages are hidden when the page is 'made editable in Gutenberg'. This is wise as it can mess up the page layout quite a bit and be confusing to content editors. However, if we do want to make them visible, so they can be editable directly from the page editor, we can.
Note - If we have lots of modals on the page, this may not be the best way to go about allowing content editors to edit them. Creating custom fields could be a better method. Also, this method will only apply to modals that exist inside pages, not modals that are setup globally.