the Course is written on two levels, pure non duality/perfect oneness, which is our true reality, and the level of the world of seeming separation, bodies, sickness and death.
This is not my understanding of the two levels as Ken talks about. They are not really levels but dichotomies. Level One contrasts Truth with illusion, and Level Two contrasts the ego with the Holy Spirit, both of which are illusions.
So that’s 4 different things, and the world isn’t one of them. The world is nothing. It is just the outside picture of our inward condition. And our inward condition depends on the choice we seem to make on Level Two.
When we get in touch with our identity as spirit, and being above the battleground, unaffected by all that seems to happen in the world of bodies, this is all really about a shift on Level Two. The experience of being unaffected by all that seems to happen is just as much an illusion as the experience of being a victim.
So yes, it’s very helpful to return our attention from the world, where we have no power, to the decision making mind, which is the dreamer, but “the level of the world” Vs “the level of the mind” is not what Ken means when he talks about the Two Levels of ACIM.
Here’s Ken’s levels explained with a little diagram https://facim.org/online-learning-aids/theory/
And here’s Ken’s chart of the universe, including that “world” we seem so obsessed with. https://facim.org/online-learning-aids/metaphysics-chart/