Qualia are experiential properties that you cannot reduce further or explain in terms of anything else. The colour red for example. Red cannot be broken down to sklee, flurb and mwow. Nor can it be explained in terms of wum or arnun. Because of this we cannot know whether anyone else experiences the colour red the same as we do. The stability of relationships between colours isn’t a problem for the idea of qualia as something un-communicable. If what you experience as green I experience as orange, we still experience the same colour relationships and apply the name ‘blue’ to their subject when discussing them publicly.
Qualia may simply be like Lisp ‘symbols’, names at some effectively random point in memory used to refer stably to a concept. There is nothing supernatural here, but there is a limit on what we can usefully or interestingly describe. I don’t find qualia a barrier to either naturalism or AI. That people experience things differently doesn’t invalidate experience or unreal it. If we all experienced the same individuality that would be a problem…