Grand Saber

This is a three part question. First, if you don’t feel Musashi fits the criteria, who among all known Saber class Servants would you say should be the Grand Saber? Second, if there are any other figures in history or other sources not currently portrayed within Fate that better fit the bill, who are they? And finally, who are those among the countless other characters within other franchises besides Fate or related works that you deem worthy of the Grand Saber rank?

Hello I just joined and am a big fan of fate lore. I was wondering if we no who the most likely grand saber is and how strong they would be in comparison to King Arthur or is there a possibility Arthur is a grand saber?