Here’s how you can disable Relevanssi Light for a particular post type. The example is shop_order from WooCommerce: you’ll need this if you use the legacy order storage. Otherwise, Relevanssi Light will stop the admin order search from working.
add_action('init', function() {
add_filter( 'posts_search', function( $request, $query ) {
if ( 'shop_order' === $query->query['post_type'] ) {
remove_filter( 'posts_search', 'relevanssi_light_posts_search', 10 );
remove_filter( 'posts_search_orderby', 'relevanssi_light_posts_search_orderby', 10 );
remove_filter( 'posts_request', 'relevanssi_light_posts_request', 10 );
}
return $request;
}, 1, 2 );
}, 11 );