Kastrup: Idea of the World

No. I'm assuming the opposite, that qualia can't be reduced to something else. That is how I'm understanding (idealist) qualia.

You're trying to understand an Idealist concept through your Physicalist lens, so of course you won't be able to understand it properly, through that perspective.

Qualia cannot be reduced to matter and physics, but that doesn't mean different consciousnesses cannot experience the same fundamental Qualia differently.

Indeed, that's how it is. We never experience a fundamental nature of Qualia ~ only a subjective interpretation of it.