Here's what worked for me since symbology also got dropped, as well as popups.
If you edit the feature service in ArcGIS Server Manager, it will create an entry in ArcGIS Enterprise portal where you can then click is visualization tab and set these sorts of things with the integrated map viewer UI for the defaults. I opened the cdf layer in Enterprise, then click Settings, then the Visualization tab appears, which gives you the mapviewer where you can set the layer labels or symbology.
