The PS4 and PS5 version are the exact same version. Same textures, view distance etc. But the PS5 Pro has the ability to upscale/enhance PS4 games. So if you play the PS4 version on your PS5 Pro it looks a bit sharper and has added fake HDR.
I let both version of BO2 run simultaneously and compared em cause I couldn't believe my eyes. The PS4 version looks a bit better. How much can they fck up lol
Screenshots here to compare, look at the weapon rail, trees and roof of the Van.
It's more visible directly on console without Screenshot compression and my editing compression. It's not a big difference but if you let both version run, you will see it.
Edit: Even more compression due to Reddit. It's really way more visible ingame lol