I'm trying to configure layers in the New Map Viewer. I want to try clustering and some different point symbology. I've tried multiple browsers but I just get a blank panel where I can't configured anything. I'm using 10.9.1 and I'm trying this with hosted and registered feature layers. Nothing works.
Have you read the considerations at the bottom of this page:
https://enterprise.arcgis.com/en/portal/10.9.1/use/configure-clustering.htm
Not sure if you're using WGS84 or Web Mercator coordinate systems?