In Scene and Web App Builder app based on Scene can one see and turn on/off elevation layers in the layer list. This is very usefull for comparing different terrain layers, for exemple before/after terrain modifications, or existing/projected terrain. 3D-widget can be use on different elevation layers.
But isn't it possible to do the same in Experience Builder? I can't see the elevation layers in the layer list...
While the Layer list widget doesn't list the Ground layers, you can use the Elevation Profile widget to visualize your elevation layer for a segment and turn it on and off from within the widget. See related post > Overlay multiple elevation layers to compare profiles