You're acting like it's struggling at 4k/60+ when it's not so no matter how elaborate you say it? You can't trump it when better is available already
Internal res is 1440p. Only the output size of the frame is 4K, cause of upscaling from the lowered base resolution. And you could more than likely get an image just as clean (and cheaper in terms of resource cost) with a 1080p base since it cleanly divides with 2160 - on top of better performance.
If the output frame size is all it takes to say "it's 4K!!" then 4K was achieved long ago with the PS4 Pro and One S just upscaling the frame to 4K.