Sometimes I think that I could easily comprehend any idea, as long as I carefully read about it.
...then I see stuff like this and realize there are ideas so far beyond my current understanding that I feel like I'd need a PhD to wrap my head around them.
Not really. The more correct terminology in the comic should have been 'voxels' (volumetric pixels). But it's definitely talking about matter quantization.
The holographic principle (a) is far from being strongly indicated for non-black hole circumstances, and (b) only relates to how 4 dimensional coordinates might map to two dimensional foundations.