Customize the default settings implemented on SearchWP activation

functions.php

<?php

function my_searchwp_initial_engine_settings( $settings ){
  
  // $settings contains all of the default engine settings
  // you can customize the weights in any way you see fit
  // but do not alter the structure of the array, just values
  
  return $settings;
}

add_filter( 'searchwp_initial_engine_settings', 'my_searchwp_initial_engine_settings' );