Only index published posts via ACF relationship fields

<?php

add_filter( 'facetwp_index_row', function( $params, $class ) {
    if ( 'YOUR_FACET_NAME_HERE' == $params['facet_name'] ) {
        $post_id = (int) $params['facet_value'];
        if ( 'publish' != get_post_status( $post_id ) ) {
            $params['facet_value'] = ''; // empty the value to prevent indexing
        }
    }
    return $params;
}, 10, 2 );