And if I leave the name field blank and the cursor there “if your text insertion point is in the name field of this trigger and you connect (or turn on) the device, Keyboard Maestro will fill the name in for you” doesn’t do anything. The quote is from https://wiki.keyboardmaestro.com/trigger/USB_Device.
@Nige_S has identified the right trigger. I've used it for my ingestion routine for years (I use a "name matching" with OR (|) delimiters between all the card names I use).
One caution with this approach is not to reformat your card in the camera without renaming it. Olympus, if I recall, renames the card UNTITLED when you format, although not all camera manufacturers do that.