oliverdavies.uk-drupal-old/web/modules/custom/talks/opdavies_talks.install

<?php

declare(strict_types=1);

use Drupal\opdavies_talks\Repository\TalkRepository;

/**
 * Set talk type for all existing talks.
 */
function opdavies_talks_update_8001(): void {
  $talkRepository = \Drupal::service(TalkRepository::class);

  foreach ($talkRepository->getAll() as $talk) {
    $talk->set('field_type', 'talk');
    $talk->save();
  }
}