I love SCM both for its music and the LSD lyrics, which Hendrix was a master of. That said, the use of feedback as a real musical tool more than a special effect, plus all of Hendrix’s other tricks and innovations, were all being played with in various ways a long time before that.
The Beatles “Paperback Writer” introed with feedback as did Steppenwolf’s “Magic Carpet Ride.” The Beatles were also already using backward loop recording consistently.
Hendrix’s style was sui generis. Unlike Clapton, he didn’t play repeating licks that built on each other; but unlike Beck, he didn’t go Full Monty and dive into solos that were more of an expression of how odd they could be without leaving the original song. I really can’t describe Hendrix.
I would call him “heay metal,” but certainly not in the vein of Iron Maiden or Metallica. That’s what makes him so evergreen-—his style was unique and so different from others’ that even today it seems new.
I never thought of Jimi as metal - I also never got the "Zeppelin is metal" theory so maybe the problem is me. But there are tunes of Jimi's that have a metal attitude, like Can You See Me at Monterey. By that "attitude" metric, even The Who and of course the Fudge could be metal. Personally I consider Wagner to be the father of metal (the overture to The Flying Dutchman seals the deal for me) but I can see where someone thinks Jimi or Blue Cheer or some other band "birthed" metal.