Custom - show "premium" terms first

functions.php

<?php

/**
 * Grab the premium posts and _intersect_ them at the beginning of the final ID array
 */
add_filter( 'facetwp_filtered_post_ids', function( $post_ids, $class ) {
    $premium_query_args = array(
        'fields' => 'ids',
        'facetwp' => false,
        'post_type' => array('photographer', 'videographer'),
        'post_status' => 'publish',
        'orderby' => 'rand',
        'posts_per_page' => -1,
        'tax_query' => array(
        'relation' => 'OR',
            array(
                'taxonomy' => 'photographer-category',
                'fields' => 'slug',
                'terms' => 'premium-member-photographer',
            ),
            array(
                'taxonomy' => 'videographers_category',
                'fields' => 'slug',
                'terms' => 'premium-member-videographer',
            ),
        )
    );

    $premium_query = new WP_Query( $premium_query_args );
    $premium_ids = $premium_query->posts;

    // narrow premium IDs to those contained within $post_ids
    $premium_ids = array_values( array_intersect( $premium_ids, $post_ids ) );

    if ( ! empty( $premium_ids ) ) {
        $temp_post_ids = $post_ids;
        $post_ids = $premium_ids;
        foreach ( $temp_post_ids as $id ) {
            $post_ids[] = $id;
        }
    }

    return $post_ids;
}, 10, 2 );