I think it’s basically even, the PS5 is punching above it’s weight, but in a game with this much streaming (at least while driving) it‘s honestly what I‘d expect, that’s niche.
I’m playing in raytracing mode (30fps) on SX and I still get noticeable FPS drops blitzing through busy unknown areas at 180 MPH and getting bombarded with phone calls (I even crashed the game doing this), but every framerate drop there just seems like an IO hitch similar to what you got in Arkham Knight on old gen consoles like if you went too far too fast, like it basically pauses for a second trying to catch up (although shorter in CP2077). Stuff like that I would assume PS5 might handle better from the faster IO and the slightly smaller file size. The indoor stuff that’s more static the SX probably takes it when the streaming is negligible.