The name of Tengri – Sanskrit perspective

I had a pleasure of meeting   Bakhtiyar Amanzhol at the Musical Geographies of Central Asia conference. His presentation Musical Instruments of Tengrianism was very informative and  interesting but  I could not quite agree with the  etymology of  “Tengri”:

“The historical roots of Tengrianism extend deep into history. The earliest references to Tengri date back to the 4th century B.C.: in ancient Mesopotamia the name of a king would be written with an honorific title, “Dingir” (God).  It has been argued that by the twelve-thirteenth century A.D. this form of worship had become a religion in its own right, with its own ontology, cosmology, mythology and demonology.  Variants of the word tengri, usually meaning “god”, are found in a wide range of Turkic languages, and there have been many speculations about its etymology. The Russian researcher of Tengrianism, Rafael Bezertinov, conveys a sense of its meaning for Altaic worship by collating the Turkic word “таң” which means “sunrise”, with the ancient Egyptian word “rа” which means “sun”, and the Turkic, Altaic word “yang”, meaning “consciousness”. “

I find the etymology, proposed by Rafael Bezertinov particularly doubtful.