I usually build maps on ArcGIS Pro, and upload them on ArcGIS Online. On Pro I can edit the symbology using my styles, and once they are on AGOL, the symbology is pretty much final. This is because the symbology on AGOL is very limited compared to PRO.
One workaround would be to overriding the web layer. It updates the default symbology of the layer, which I can bring it back on the map on AGOL. However, to do that I need to Export the layer to local GDB (losing all domains, which is a big deal), so them I can override (I cant override if Im already using a weblayer).
I could also use the custom icon option on AGOL, but it only accept images. Maybe if there was a way to export symbols form Pro to images, I could upload them.
I cant override a map. Would be nice if I created a map on Pro, and just chose to override it, so it would update the symbology.
In the end, my question would be if there is any tricks to work with symbology on ArcGIS Online. Anyway ideas on how to update them based on a Pro map, or copying the symbology from another AGOL Layer. In the end looks like that I have to redo entire maps, surveys, and apps just because I want to update the symbology.