Having the same issue here and do not really want to change the ACF field to a post field. As a last case scenario, you could create a page that then redirects to the custom post archive page.
In my scenario, I was creating a directory page listing all of the common types of pages I’d want to be linking to. Therefore the custom post type archive page was one of them.
Day after Gutenberg has been released into WordPress 5.0 core and I still don’t see a block option inside the field groups?
Any follow ups to this would be much appreciated!