While actually looking for something quite different, I managed to stumble over this, by Prof Jamie Hubbard.
Shows up, for example, a range of different takes on whether there is much in the way of "thing-ness" there. And, even when there is, to what extent and whether or not it is similar to the Upanisads (for instance).
One can cut to the chase scene at pg. 11.
My recently moved Blog, containing some of my writings on the Buddha Dhamma, as well as a number of translations from classical Buddhist texts and modern authors, liturgy, etc.: .