Solved it 3 minutes after posting this by just using acf_add_options_sub_page
and setting the parent_slug
to the URL of the custom post type:
if( function_exists('acf_add_options_sub_page') ) {
acf_add_options_sub_page(array(
'page_title' => 'LOLP Locations',
'menu_title' => 'Manage Locations',
'parent_slug' => 'edit.php?post_type=loan-originator',
));
}