I have an old compare analysis app which compared four separate web maps. I can no longer configure it to point to a different set of maps, and the only comparison app I can find now only supports two maps.
Is there a way to reconfigure the old app, or configure the new app to support four different maps?
The old Compare app is still available, though now considered a legacy app:
https://www.arcgis.com/home/item.html?id=a35a934152dc44dda8d793a2303f0df1
The newer compare/swipe apps are listed and discussed in this blog article:
https://www.esri.com/arcgis-blog/products/arcgis-online/mapping/swipe-compare-apps/
In practice, adding a lot of maps to a comparison limits the visibility/exploration of those on all but the largest monitors/devices.
An alternative you might consider is using Experience Builder to create the comparison experience you like. The basic 2 map comparison using ExB is discussed and shown in the blog article above.