Add secondary sort to SearchWP results to sort matching relevance results by Title in ASC order

searchwp-customizations.php

<?php

// Add secondary sort to SearchWP results to sort matching
// relevance results by Title in ASC order.
add_filter( 'searchwp\query\mods', function( $mods, $query ) {
	global $wpdb;

	$mod = new \SearchWP\Mod();

	$mod->set_local_table( $wpdb->posts );
	$mod->on( 'ID', [ 'column' => 'id' ] );
	$mod->order_by( function( $mod ) {
		return $mod->get_local_table_alias() . '.post_title';
	}, 'ASC', 99 );

	$mods[] = $mod;

	return $mods;
}, 30, 2 );