"The tales are clearly part of the same tradition, yet, by placing the image of the sword god in conjunction with celestial deities at Yazilikaya, the Hittites retained an association that the Arthurian variant has lost: the tale of the Sword in the Stone had something to do with the stars."
Indeed. And since the frequent and nearby enemy of the Hittites, the "Mittani" (Medes? or Metayn: Bedouin for "the 100 sons") are historically attested to be Vedic god worshipers and gave a sword to Amenhotep II which appears to be the sword found in Tut's sarcophagus, we might have an alternative theory.
Which is: Tut's sword is proven by testing to be of meteoric origin...or "something to do with the stars." Vedic...later Hindu, tell the tale of the Blacksmith god Visnu(Vishnu) forging a "celestial weapon" for Shiva (TaiShub/King Sheba, the Hittite "Storm God, married to Shauska/Istar...the Queen of Sheba). Curiously then, who would be the forger of that sword in Mittani history? Could it be King "Arta-tama" the father of "Tushratta" the sworn enemy of the Hittites? The timelines would match with Amenhotep II. The Mittani are said to have forged "Natas"/Black metal/Iron by the river Khabur.
Curious also: I found a 1600s AD book in Italian, history book, that spells Amenhotep/(Greek Amenophis) as Ame Nu Phis. Reading the word the "wrong direction" would give us PhisNu...Vishnu...in Thai, his name is Phitsanu.
Pulling a sword from a stone....forging it from a meteorite? In Thailand, in the city of Uttaradit (Uthar and Aditi?) they tell a tale of reforging a special sword that had been broken...
I believe the royal titulary hieroglyphs of Amenhotep III depict this sword being held aloft by the king...Ankh Keperu...Ankh/Ex Khabur/Calibur?