Congratulations to NXG!
So he does confirm PS5’s smaller game install size is due to Oodle compression. Nice!
If it is due to Oodle compression, then PS5 giving up a few secs of load speed for tighter compression would be a great tradeoff for PS5's limited storage size.
Not to derail the topic of misaligned reflections but I found the above to be more interesting.
Specifically because this would imply that the XSX version is not using BCPACK, since BCPACK should produce very similar results to Oodle Texture + Kraken. By extension that means the XSX may not be using it's hardware decompression block while the PS5 is, thus putting a greater load on the CPU which may have to stand in for the decompression. This could explain why the IO is being blamed for the stutters. Rather than it being down to the PS5 having a faster IO system (the XSX should be more than sufficient for anything this game needs) it's more a case of the XSX system not being fully utilised.