This problem just recently started. I believe I upgraded my Mac M1 to Ventura and updated Lightroom to the latest version since this stopped working. I have no problem using Nikon transfer to transfer the images from both cameras.
When I select Add Photos in Lightroom then select Connected Devices (Lightroom does recognize both cameras when they are connected), I see the camera flashing its green indicator as it typically does to reflect that Lightroom seems to be reading. While it is reading, Lightroom displays the message "No images can be imported...." Prior to this issue, that message would be displayed until Lightroom finishes reading the camera or camera card. Now that message remains indefinitely.
So I am wondering if there was something in either the OS update or Lightroom update that has caused this to stop working.
I posted this message in the Lightroom Classic group by mistake and it seems this was corrected in version 12.1 but not in the cloud based version 6.x.