Looking for way to display a group of nodes and their sub-folders in the same widget


The obvious answer might seem to be WebReports but a WebReport for custom node browsing seems to only work in classic view - I need this to work in Smart View. And given that I'm dealing with a government client, I can't do a custom widget because that means a custom module (just so you can update a single Javascript list as I recall).

I'm looking to display something like

Folder A

* Sub-folder A1

* Sub-folder A2


Folder B

* Sub-folder B1

* Sub-folder B2


And each of the sub-folder levels gives you all the stuff you would get in a node browsing table. This was relatively easy to build in Classic UI as you had more control over the UI there. I thought about the Content Intelligence Nodes List and Table WebReport, but I cannot find any documentation for them. At the very least I would like to know what sort of output the WebReport is expected to produce.