I have created my own feature layer and specified that it should have z. It seems that elevation information recorded when I use the layer with Field Maps is put in a field called esrignss_altitude, but when I load that layer in a WebScene and view the points I've collected by rotating the view such that I can see their elevation, the ones with the largest altitude don't seem to be raised the most above the map. I can't actually tell what's causing the heights of the points.
Additionally, it would be great if I knew what post labels and post tags are, and how to know which are appropriate, but that's less important to me right now. :)