I have had no problem following the very informative blog posts and GeoNet threads on using Arcade expressions to show information from multiple overlapping layers in a single popup. However, I have a tangentially related issue that I couldn't figure out how to do using FeatureSets and Intersects in Arcade.
I have a layer with multiple overlapping polygons. There are basically 2-11 duplicate polygons for each area. For various reasons due to back infrastructure and reasons I don't understand, we can't condense these into a single polygon with multiple attribute fields. I would like to have the popup for each of these show only a single time while showing a single selected field from each of the other overlapping features. However, I'm not sure how to do this or if it can even be done.
So I suppose:
1) Is it possible to reference overlapping polygons within a single feature layer in a single popup?
2) And where would I start using Arcade to do that?