Unless something has changed since, Digital Foundry put out a fairly lengthy video pointing out that the PS5 version has some pretty irritating bugs compared with the PS4 (and PC) version of the game. Like yes, it's running in a higher resolution on different hardware so it's not necessarily going to perform better overall, but it has these crazy stutters and sudden drops in frame rate when the camera is pointed toward certain things that aren't even necessarily being drawn to the screen.

It depends on how you define "optimization" of course, and I don't think your estimates of exactly what PC and PS5 hardware can handle are accurate, but its main issue is these bugs they need to fix that cause it to run worse than it should.