@olivierlambert
I think I just solved it.

I executed wget https://archive.org/download/tiny-iso-test/TinyIsoTest.iso from /Local_ISO, and that ISO showed up just fine.

I had loaded my earlier ISO's into "brand" subdirectories.
For example, /Local_ISO/Microsoft/WindowsServer2022.iso"

It appears that such sorting is not supported.
I moved both ISO's up one directory and both are now visible.
For example, /Local_ISO/WindowsServer2022.iso" works just fine.

Thanks-a-bunch for the help.

@olivierlambert
I did previously try to "rescan".
My ISO's were *.ISO.
Just to exactly match your recommendation, I renamed them both to .iso extensions (lower-case).
Then rescanned again.

Still nothing listed in Disks. Just that "No VDIs in this storage" message.

Tried to create my first local storage ... just a local ISO repository.
The SR creation was successful and error-free.
But the Disks tab only says, "No VDIs in this storage", and searching for that message in this forum yielded only one result. That result was for a different use-case.

I am following a youtube tutorial. Here's the point in the video where the relevant instruction begins.

I downloaded two ISO's onto the XCP-ng host into /root/Local_ISO.
Then, in XOA, I selected New>Storage and provided all appropriate details.
Storage Type: ISO SR > Local
Path: /root/Local_ISO

The SR was created, and I expected to see my two ISO's under the Disks tab. But instead it just shows the message, "No VDIs in this storage".

The General tab does show almost 12GB used, though, so it seems that the storage is being read and recognized.

What do I need to do differenetly to make those ISO's visible and accessible?