When our eyes look at the world, all we get are a series of 2D flat images.
Our brain mixes the two images of the eyes and constructs a 3D virtual model from those cross cuts. So we see a kind of mental construct of the room around us, but we do not get every single possible 2D slice from every angle at one time, only the view from where our eyes are located in relation to the rest of the room. Thus some one else in the very same room, has a different mental consctrution of the room. We also combine the different constructs from memory as we move about the room, to create a not immediately seen construct of the room, but a inner combination of many diffent perspective angels, into a single room. But these are all mental constructs, all we ever actually see are various 2D slices.
But the room exists independent our our seeing it, it is really 3D and it's real 3D space transcends all of our constructs based on 2D images. Thus malkuth is out virtues models but the real reality of the Supernals is the actual real physical room, that transcends all individual constructed models of the room.
The room is not in your mind, the mental construction build out of 2D slices is in your mind. As is everything you ever directly experience or know about anything, is actually a virtual construction put together from cross cuts and limited input filtered through your sense organs and brain that makes this constructs.
But beyond those constructs is the real physical room, with physical matterial objects, which are only hinted at and distorted as the brain tries to model them from limited sense data. The brain is itself a physical object, that is part of that room, part of the whole universe of reality that exists outside if the mental constructs. Your idea about a brain, is a mental construct that refers to but is not the brain itself.
Reality is physical and it is analogous to what we see and touch and experience, only our experiences are constructions which are subject to flaws, since they use limited data and fill in the blanks between cross sections of sense data, also the physical reality includes elements that our sense organs do not pick up. (no that does not mean angels, ghosts, and astral planes, those are things that your brain creates to model experiences and events that come from unusual sense perceptions, that the brain doesn't quite know what to do with, but also does not ignore, misperceptions and cognitive glitches) Reality does contain light wavelengths we can't see, sounds we can't hear, organisms too small to see, etc.
reality is not a construct of your mind, but your personal perspective is a construction of the brain tying to gather loose cross cuts of limited sensory data. So in a sense everyday phenomena are illusions just as much as the effects of rituals are illusions. Only the models we use everyday are tested constantly refined to fit the real world, while seeing an angel in a dark mirror, is the result of an ambiguous sense data, fleeting in nature, causing the brain to construct some explanation and project it into the model of the world around you, as a best fit for some bit of inadequately perceived data. And the communication with such spirits is a communication between parts of the brains processes working on assumptions and trying to build a coherent explanation and rationalization of the strange sensory data, processed through an unusual trance state of cognition.
Crowley says as much in "the initiated understanding of ceremonial magic"