Hi Jonathan,
After tinkering around with WFM, I understand the limitation much better. I think it is due to the misleading documentation for "update-job-properties";
https://enterprise.arcgis.com/en/workflow/latest/help/update-job-properties.htm
"The Update Job Properties step allows the person running a job to update extended properties and the following job properties:"
The truth is, it doesn't let you update all extended properties. In my testing it only works for extended properties if you add the table. However survey123 is considered an extended properties but it does not allow you to update field in survey123 other than the linked field ID. (globalid).
It would have been great if it does allow you to edit specific field in a survey123 extended properties.
Similiar issues raises:
https://community.esri.com/t5/arcgis-workflow-manager-questions/workflow-manager-server-and-extended...