The “dualism of the Force” is a total accident. Do you honestly think GL even considered anything like that? He just wanted to throw in his Midi-chloriens as random technobabble because it was referenced in an old rough draft. Then, he could further “prove” his “original vision” claims.
I don’t see any reason to doubt it because the PT presents an alternate view of so many things we know from the OT, if it was only that, maybe. But on the whole it is clearly subversive. And it’s well known that George was distancing himself from the simplistic black and white view already by the time of ROTJ with Obi-Wan’s “point of view” speech.