ArcGIS Enterprise 10.9.1, subscriber content is enabled within our organization and Living Atlas content is enabled.

In the Classic Web Map viewer, there is an option to add directly from the Living Atlas

There is a Content tab for Living Atlas as well:

Using the Add Data widget in the Web AppBuilder web app however, there is no Living Atlas to search from:

If I use the same search within the AppBuilder as I do in Map Viewer, no results are found:

This Esri blog post here suggests that you can enable subscriber content in Web AppBuilder (although I really don't care about subscriber content, we just want Living Atlas):

However, the attribute pane looks nothing like this in the WAB in Portal:

Why is it that we cannot add Living Atlas layers in WAB in Portal but we can add and use Living Atlas Layers in the Map Viewer?