I've added a new select field to a post type and if I set the query_args (linked to a relationship), I can filter the default options available to select. I'm setting the to field to the user's ID manually to test, ie where to is user id 4.
But I need this to be based on the currently logged in user. Is this possible? I've searched and the answer seems to be no.
Currently, it is not possible to add a function to query_args settings in the builder. Please use the code to register the custom fields in this case to assign a parameter to a function that returns a value.