Is there any hook or event that is fired when user data is set/updated/deleted
hook_entity_presave (hook_ENTITY_TYPE_presave)


  Act on an entity before it is created or updated.
  
  You can get the original entity object from $entity->original when it
  is an update of the entity.


hook_entity_update (hook_ENTITY_TYPE_update)


  Respond to updates to an entity.
  
  This hook runs once the entity storage has been updated. Note that
  hook implementations may not alter the stored entity data. Get the
  original entity object from $entity->original.




Here's a sample implemented by system.module:

/**
 * Implements hook_ENTITY_TYPE_presave() for user entities.
 */
function system_user_presave(UserInterface $account) {
  $config = \Drupal::config('system.date');
  if ($config-&gt;get('timezone.user.configurable') &amp;&amp; !$account-&gt;getTimeZone() &amp;&amp; !$config-&gt;get('timezone.user.default')) {
    $account-&gt;timezone = $config-&gt;get('timezone.default');
  }
}