You’re right (of course.) But I WAS confused. I right clicked on the image in grid mode and while there were lots of choices, favorite was not one of them. There really was no way to know. Going to the 1 image view (for view or edit) is not convenient because the whole point is to see images side by side, as in the grid, and decide favorite vs. not. I may have shot three very similar images of a swan and want to see them side by side and choose the one I like best.
So: now that I know I don’t need the feature anymore. But I suggest making it apparent even in the grid display that you can use . and I assume 1,2,3,4,5 directly from there,