Can’t import a folder in Windows LRC

I'm trying to import a folder of raw files but LRC seems to be treating them as if they already exist in the catalog, which they don't.

Did you actually look in the catalog to see if the photos are in there? Please follow all four of these steps in sequence and report the results:

1. In the Lightroom Classic Library Module, on the left, under Catalog, click on All Photographs
2. Turn off all filters (Ctrl-L once or twice)
3. Turn off all stacking (Photo->Stacking->Expand All Stacks)
4. Search for at least one of these photos by file name using the Lightroom Classic Filter Bar

Now the example below does not exactly follow your situation. In this case I am looking at photos already existing.

So LrC v13/5 (and perhaps older) is preventing me from accidentally importing images already in the catalog. With or without the Do not import suspected duplicates option on.

(Oh one typo in the screenshot, if I Mouse HOVER over an image, not Mouse Click, I see that it is already imported)

Moving on, in your case you state that you get the same result when attempting to import new photos, correct? Can you share a similar screenshot?

First, Camera Raw is not needed for LrC since it has it integrated.

Are you trying to import from an attached card reader or alike, and you select "Add" in Import by coincidence?

Or, do the files have the same numbering from the camera as files before? This happens if the counter in the camera is set back to start over, for instance.