At risk of doxxing, this brings up an original idea that I thought I would share. That said, maybe it's only a crumb on the shoulders of giants.
This image attempts to correlate various schemes across traditions into a integrated understanding about states of consciousness. What I noticed about a decade ago was that the states in the traditions and reflected in the image are structured as a sequence of concentric rings, I suppose to show the phenomenological sensation of ever-greater awareness. However, that structure is based on the phenomenological sequence of experience! Aka, all of our traditions to explain consciousness come up with the same parallel structure, BUT that structure is premised on the sequence of experience, NOT NECESSARILY the actual relative structure of the states to themselves. It causes a big dilemma because consciousness is trying to become conscious of itself, so experience seems like the only way to have any feedback. On a phenomenological level this is correct, but on an ontological level, all of humanity's traditions for coming up with an "objective" or a "relational" structure of the states may be wrong. We've jumped to that conclusion in the traditions based on the hermeneutical sequence of experience.
I'll use the HINDU terms because they're more neutral for me.
Sequence: Gross-Subtle-Causal-Turiya-Turiya Tita
OR
Sqeuence: Waking-Dreaming-Deep Sleep-Witness/Lucid-Non-dual
All the traditions seems to agree on this sequence.
Without getting into it, a more likely objective structure seems to be that Gross and Subtle are two sides of the Causal coin, like oil and water around a meniscus. Moreover, to us, the meniscus seems a secondary emergent, but that may be somewhat of an illusion because of our relative perspective within "consciousness". The Witness or Turiya then follows the phenomenological sequence suggestion as the fourth in line, a step away and giving perspective on this dual and emergent causal construct. Finally, non-dual moves beyond and/or into and all those other fluffy ways people like to talk about it to realize that the witness is the construct, etc.
I hope I haven't lost you at this point, but to bring it to your idea about the left hand path and dualism, even monism, etc., there is a lot of confusion in spirituality. Religion identify with either the gross or the subtle(exoteric vs esoteric, etc.), but miss the causal and the overall relationship between the 3. Alternatively, even within, another understanding is to value the witness over the observed gross/causal/subtle. This is partly to do with a bit of the gordian knot of extrapolating the state sequence of gross/subtle/causal into a map of spiritual liberation. People just go in circles.
I leave it at this for now, and see how the cookie crumbles…