I didn’t think about using pre_get_posts so that’s an interesting approach, however the problem is the relationship field is inside of a repeater (so there’s more than one) and I want to be able to do this for _acfuploader fields in each repeater. So custom_field_name would need to be the relationship field that belongs to the same repeater row as the uploader.
Not sure if that’s possible using a query filter.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users