But you did not comment on this:
And since, in a non-dual state, the experiencer is the experienced, the experiencer must also be an illusion. So we could all be merely part of a computer simulation such as The Matrix and the Buddha is part of that as well. Or the Hindu belief that we are all the dream of the God Brahma is correct and Buddha is also part of the dream.
And that would be a problem.
The fact that you did not comment on the above is to me, a reflection of the difficulty of avoiding the extremes of unconditioned and conditioned, and by extension the extreme position of the other mutually exclusive pairs such as permanent and impermanent, existence and non-existence etc. by using those very words, ie. words such as conditioned and unconditioned etc.
It depends on what you mean by nondual. There are three kinds of non dualism. One is cognitive non dualism, i.e., everything is consciousness, for, like example Yogacara. The second is ontological nondualism, i.e. everything is brahman, god, etc. The third is epistemic nondualism, i.e., being, non-being and so on cannot be found on analysis and therefore do not ultimately exist.
The indivisibility of the conditioned and the unconditioned is based on the third. We have only experience of conditioned phenomena. Unconditioned phenomena like space are known purely through inference since they have no characteristics of their own to speak of. When we analyze phenomena, what do we discover? We discover suchness, an unconditioned state, the state free from extremes. That unconditioned state cannot be discovered apart from conditioned phenomena, therefore, we can say with confidence that the conditioned and the unconditioned are nondual. The trick is which version of nonduality you are invoking. This nonduality of the conditioned and unconditioned cannot apply to the first two nondualities for various reasons.