Raphael's School of Athens: Is it Heraclitus or Epictetus?

Towards the end of 2020, while doing some work on a college research paper, I found an image of Epictetus I had never seen before.  I was exploring my college's various research engines and one of my searches yielded an image from the British Museum; an drawing of Epictetus.

You can find the print here: https://www.britishmuseum.org/collection/object/P_1935-0828-5

The description states, "Epictetus: bearded man seen head and shoulders, head resting on his left hand; on white ground; detail from the School of Athens, after Raphael"

The artist who drew this image of Raphael's School of Athens is Antonio Regona and he would have drawn it sometime between 1775 and 1853, according to the site's data on 'production date.'

He drew other objects from the School of Athens; see this link to his works at the British Museum: https://www.britishmuseum.org/collection/term/BIOG191367

• Epicurus
• Zeno of Citium
• Diogenes
• Plato

Now to the question.  As I've studied a bit about the painting, I've come to learn that there seems to be wide consensus that the image that Antonio Regona claims is Epictetus, is in fact Heraclitus.

The wikipedpia page on the painting claims it is Heraclitus: https://en.wikipedia.org/wiki/The_School_of_Athens

The site Art in Context claims it is Heraclitus: https://artincontext.org/the-school-of-athens-raphael/

But perhaps the best information or analysis on this figure comes from the BBC and talks a bit more extensively about him: https://www.bbc.com/culture/article/20200910-the-school-of-athens-a-detail-hidden-in-a-masterpiece

This article, too, claims he is Heraclitus, but also notes that this figure and many of the other figures are deliberately ambiguous.

So, perhaps, Antonio Regona may have known more about this figure or he chose to not claim this figure as Heraclitus, but Epictetus.  Perhaps Regona had seen another image of Epictetus by William Sonmans - the image that many of us may be more familiar with (link: https://commons.wikimedia.org/wiki/File:Epicteti_Enchiridion_Latinis_versibus_adumbratum_(Oxford_1715)_frontispiece.jpg)  This image would have been created prior to 1715 and would pre-date Regona's drawing.

Both images show Epictetus, holding his head up with his left hand, while writing.  Perhaps these two clues are why Regona claims the figure in the School of Athens is Epictetus and not Heraclitus.

In conclusion, it's a interesting mystery and piques my curiosity about why would Antonio Regona call that figure Epictetus and not Heraclitus.