Exclude Post Types From ACF Links Modal

Hi. I’m working on a movie database type site and I’m using ACF to add Custom Fields to Custom Post Types like ‘Movie’ and ‘Cast & Crew’ etc. One of the fields is a ‘Link’ type with the Return Value set to ‘Link Array’.

When adding a new Link on a new Movie post type for example, the Insert/Edit Link modal box pops up as expected, where users can add a URL and Link Text but also search for existing content. The search query below the search box automatically adds *everything* including Pages, Templates and Post Formats generated by other plugins. How can I filter this to only show/search for specified custom post types? In this case, I’d like to only show and allow users to search for posts from the Movie and Cast & Crew post types.

As far as I can tell, this might be using WordPress’ own search function as the UI looks the same as when adding URLs on standard post/pages, so I understand it may not be strictly ACF related. But I’ve searched everywhere, installed various plugins, tried various pieces of code in my functions.php but I can;t seem to figure out how to do this.

Any help would be greatly appreciated. Thanks.