I think all of these factors play a part, but what I would like to know is the following

Under equal tempreament, each note ilt ls a compromise, or at least most of them. They can vary by different percentages. I think this may well have an effect on the 'darkness' of a key too. I don't know any source that I could use to compare though, least not one I could understand
Z


Win 11 64, Asus Rog Strix z390 mobo, 64 gig RAM, 8700k