Just in case someone else wants to use HTMLText in DataObjects and be able to publish the images that clients can upload into TinyMCE - SilverStripe 4

DataObjectLinkTracking.php

<?php

namespace Vulcan\Common\Traits;

use SilverStripe\Assets\File;
use SilverStripe\Forms\FieldList;
use SilverStripe\ORM\HasManyList;

/**
 * Trait DataObjectLinkTracking
 * @package Vulcan\Common\Traits
 *
 * @method void augmentSyncLinkTracking
 * @method HasManyList|File[] ImageTracking
 */
trait DataObjectLinkTracking
{
    /**
     * Remove fields added by SiteTreeLinkTracking
     *
     * @param FieldList $fields
     */
    public function removeTrackingFields(FieldList $fields)
    {
        $fields->removeByName(['LinkTracking', 'ImageTracking', 'BackLinkTracking', 'HasBrokenFile', 'HasBrokenLink']);
    }

    /**
     * Call in onBeforeWrite of parent
     */
    public function trackDataObjectLinks()
    {
        $this->augmentSyncLinkTracking();
    }

    /**
     * Call in onAfterWrite of parent
     */
    public function publishTrackedImages()
    {
        foreach ($this->ImageTracking() as $image) {
            if (!$image->isPublished()) {
                $image->publishSingle();
            }
        }
    }
}

Add to the DataObject:

use \Vulcan\Common\Traits\DataObjectLinkTracking;

private static $extensions = [
    SiteTreeLinkTracking::class
];

public function onBeforeWrite()
{
    parent::onBeforeWrite();
    $this->trackDataObjectLinks();
}

public function onAfterWrite()
{
    parent::onAfterWrite();
    $this->publishTrackedImages();
}