Duality usually refers to the imagined apprehended and apprehender, which is a delusion that leads to suffering and the causes of suffering.
Well here exactly is the dissent because the buddha taught that it is attachment (clinging, craving, grasping) which is the problem and I prefer to agree with him because my experience does agree. No need to take an "illusionist" point of view. "Illusionism" may be grounded on subtle aversion. Neither "real" nor "illusion" may be the middle way.
Then we can see it so: if we believe that object is really bad or good and the one benifitting or harming as well; the attachment and aversion suffering is there. Because of making a strong separation, people see solid through ignorance. And so we build further and all what is good to us is perfect, all other need to be shooted. And so one build the narrow self cherishing world through more and more fabrications in which one turns entangled. Illusion.
Looking along dependence, impermanence; all what 'is', is infact having no any ground for our attachment and aversion. In nondual the solidnesses, the "substantial" (insubstantial) is seen what it is, no way to get attached.
Also when the conceptual mind percieves, the phenomena is already gone. What a peace now!
"There is some pleasure to be had by scratching an itch
But it is even more pleasurable to have no itches at all
Likewise there are pleasures to be bad from worldly desires
But with freedom from desire comes pleasure greater still". Nagarjuna