Well, it will be a bit long, and I apologize for that.
First, I'll quote the blog of Planck which states the following: "
Essence. The foundation of all external matters..." alongside that quote "
The origin and source of all things is Essence!!"
The Essence by itself is the framework of everything that exists (be it elements or more conceptual things), which was something everyone understood I think.
Secondly, I'll quote those two passages from ISSTH :
Here (both are on the same link)
Here, we understand that Essence is the Dao. This means that every Dao, by definition, is Essence. Therefore the Dao of light for example is simply the Essence of Light.
Now it is very simple, if we accept every Dao as being its very own Essence, it means we can accept
the Essence of the Yin-Yang to exist too. There is no further explanation to my knowledge about the properties of said Yin-Yang besides being, obviously, opposite forces (like female/male for example).
Therefore, if there is an Essence of Yin-Yang existing, Daosource cultivators transcend it obviously and operate on either none of the duality implied by the Essence itself (which would grant TD I assume?) or their very own essence operates on a completely different and superior duality system of the "normal reality", which may grant TD too? I don't really know tbf.