Is Japanese Katakana Derived from Korean Kwukyel?

The Gugyeol script is said to be from the Shilla period in Korean history. The earliest remnants of it found in Korea thus far date from the 11th Century. So there is a which came first argument because of the chronological difference between the Japanese 9th Century records of Katakana and the later Korean historical evidence of Gugyeol that has survived. I put a link to a shorter Korean video on this subject just so the similarities in the scripts and there initial common source in traditional Chinese characters can be visualized. The video is in Korean but it has some charts or graphics which show the Gugyeol and Katakana and some of the hanja/kanji they are both related to. The relevant graphics begin to appear at about 2:32.

The video was based on a work by linguist Alexander Vovin. It's remarkable how similar the characters are. This ancient Korean script apparently fell out of use even by scholars and monks in Korea by the 19th Century. This was a big revelation to me, I had never heard of this earlier Korean writing system. It's fairly obscure. At the link below is Volvin's article explaining his theory of the connection between Gugeol and Katagana.


Is Japanese Katakana Derived from Korean Kwukyel?
Alexander Vovin
https://www.academia.edu/19256034/Is_Japanese_Katakana_Derived_from_Korean_Kwukyel
(You have to answer a couple of questions to get access. I wanted to cut and past some of it, but the PDF is actually photocopied or screenshot, so I couldn't).

He has another interesting article over there:

WHY JAPONIC IS NOT DEMONSTRABLY RELATED TO ‘ALTAIC’ OR KOREAN (pre-publication version)
Alexander Vovin
https://www.academia.edu/4208284/WHY_JAPONIC_IS_NOT_DEMONSTRABLY_RELATED_TO_ALTAIC_OR_KOREAN_pre-publication_version_

Died: 8th April, 2022.
Details of death: Died at the age of 61.
Alexander Vladimirovich Vovin was a Russian-American linguist and philologist born in the Soviet Union who served as the director of studies at the School for Advanced Studies in the Social Sciences (École des hautes études en sciences sociales (EHESS)) in Paris, France. He was a world-famous linguist noted for his work on East Asian languages.

https://en.wikipedia.org/wiki/Alexander_Vovin

https://en.wikipedia.org/wiki/Gugyeol