FacetWP – ignore radio facet selections

<?php

// Add to your (child) theme's functions.php

add_filter( 'facetwp_facet_filter_posts', function( $result, $params ) {
    if ( 'categories' == $params['facet']['name'] ) {
        return 'continue'; // prevent facet from being processed
    }
    return $result;
}, 10, 2 );