loop-all-popups-to-change-settings.php

<?php

add_action( 'init', 'my_custom_function' );
function my_custom_function () {

  $popups = get_posts( array( 'post_type' => 'popup' ) );
  foreach( $popups as $popup ) {
    $popup = pum_get_popup( $popup->ID );
    // Do stuff with $popup.
    
    $popup->update_setting( 'position_top', 10 ); // Set to 10px from top position.
  }
}