OK- When you publish a service from Pro you get;

That would imply to me that you can control all popups that may reference the service you have just published from Pro.
but, no - Overwrite a web feature layer—ArcGIS Pro | Documentation states:
"Web maps store pop-ups and symbology separately from web layers. Pop-ups stored in the web map will not be updated if the web layer is overwritten with a newly configured pop-up. If the schema of a web layer changes, you may need to reconfigure the web map's pop-ups and symbology."
So what is the point? It appears the only way to updated popups to appear on webmaps and applications based on these is to remove the originating map service and re-add.
Our work AI tells me we can zap the JSON of the webmaps and apps to reset to the initial, but have I missed the big red button that says "update popups from source" ?
We were thinking of moving a lot of our external apps to be in AGOL, but with the added overhead of updating the services several times (Portal Web map, then re-add that web map to AGOL, force apps to recognize new popups) we may have to rethink this.
Or am I totally wrong? IS there some magic I've missed?
Cheers
ACM