Programmatically create new Schedule Updates Entity Reference on Node
Here is one example of how to add a ScheduledUpdate to your 'host' entity, in your case a node.

$scheduled_update = ScheduledUpdate::create([
  'type' =&gt; 'node__sticky',
  'status' =&gt; ScheduledUpdateInterface::STATUS_UNRUN,
  'sticky' =&gt; NodeInterface::STICKY,
  'update_timestamp' =&gt; $timestamp,
  'entity_ids' =&gt; [$eventId],
]);
$scheduled_update-&gt;save();
$node-&gt;promote_event = $scheduled_update-&gt;id();
$node-&gt;save();


Good luck!