I wonder how much effort it really takes to release a game for both PS4 and PS5, especially if you're already building it for Xbox and PC. PC requires you to support a wide array of performance capabilities, at least in theory making it easy to scale back performance to a previous-gen console; and they're probably still using an evolution of the same engine they were using for PS4, so at least to my mind it's a checkbox, some performance tuning and a bunch of QA. (at least in theory). maybe some different servers to support multiplayer - but since CoD supports cross play maybe not even that.