Finding all black & white photos in Apple Photos

I see that folks have been asking since recent MacOS updates, how they can find black and white photos. I haven't seen an answer that was good.

I finally realized I could type "monochrome" as the keyword and get what seems like a lot of the images. However, it also pulled up some tinted monochrome images.

Is there a better and quicker way that is more sure to get all b+w photos? A tag that works completely?