Exporting and importing image dimensions with focal point

Scratch that. I figured out how to use your event system to avoid hacking. I'm closing this, and showing my code here in case anyone's interested.

namespace Drupal\my_custom\EventSubscriber;

use Drupal;
use Drupal\file\Entity\File;
use Drupal\focal_point\FocalPointManager;
use Drupal\media\Entity\Media;
use Drupal\focal_point\FocalPointManagerInterface;
use Drupal\single_content_sync\Event\ExportEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

class ExportEventSubscriber implements EventSubscriberInterface {

  private array $imgMimeTypes = [
    'image/jpeg',
    'image/gif',
    'image/png',
    'image/webp',
  ];
  private FocalPointManagerInterface $focalPointManager;
  private string $cropType;

  public function __construct() {
    $this->focalPointManager = new FocalPointManager(Drupal::service('entity_type.manager'));
    $this->cropType          = Drupal::config('focal_point.settings')
                                      ->get('crop_type');
  }

  /**
   * @return array[]
   */
  public static function getSubscribedEvents(): array {
    return [
      ExportEvent::class => ['onExport'],
    ];
  }

  /**
   * @param \Drupal\single_content_sync\Event\ExportEvent $event
   *
   * @return void
   */
  public function onExport(ExportEvent $event) {
    if ('file' == $event->getEntity()->getEntityTypeId()) {
      /** @var File $file */
      $file    = $event->getEntity();
      $content = $event->getContent();
      if (in_array($file->getMimeType(), $this->imgMimeTypes)) {
        $crop = $this->handleFocalPoint($file);
        if (!empty($crop)) {
          $content['base_fields']['crop'] = $crop;
          $event->setContent($content);
        }
      }
    }
  }

  /**
   * Extract the actual focal point dimensions.
   *
   * @param \Drupal\file\Entity\File $file
   *
   * @return array
   */
  private function handleFocalPoint(File $file): array {
    /** @var \Drupal\crop\Entity\Crop $cropEntity */
    $cropEntity = $this->focalPointManager->getCropEntity($file, $this->cropType);
    $fid        = $file->id();
    if (!$cropEntity->isNew() && !$cropEntity->get('x')
                                             ->isEmpty() && !$cropEntity->get('y')
                                                                        ->isEmpty()) {
      $media_ids = Drupal::entityQuery('media')
                          ->accessCheck(FALSE)
                          ->condition('field_media_image.target_id', $fid)
                          ->execute();

      // to populate the crop height and width,
      //   we need to back-reference to the media entity that uses this image,
      //   because the crop entity isn't saving it.
      if (!empty($media_ids)) {
        $media_id           = reset($media_ids);
        $media              = Media::load($media_id);
        $height             = !empty($media->get('field_original_image_height')
                                           ->getValue()) ? $media->get('field_original_image_height')
                                                                 ->getValue()[0]['value'] : 0;
        $width              = !empty($media->get('field_original_image_width')
                                           ->getValue()) ? $media->get('field_original_image_width')
                                                                 ->getValue()[0]['value'] : 0;
        $x                  = !empty($cropEntity->get('x')
                                                ->getValue()) ? $cropEntity->get('x')
                                                                           ->getValue()[0]['value'] : 0;
        $y                  = !empty($cropEntity->get('y')
                                                ->getValue()) ? $cropEntity->get('y')
                                                                           ->getValue()[0]['value'] : 0;
        $cropDims           = $this->focalPointManager->absoluteToRelative($x, $y, $width, $height);
        $cropDims['height'] = $height;
        $cropDims['width']  = $width;

        return $cropDims;
      }

      return [];
    }

    return [];
  }

}