They were stupid to advertise the PC version in the PS5 commercials. That likely negatively affected sales of the game on PS5, if in fact Square-Enix are in any way "disappointed" with sales there.
It's like getting mad your new car has slow sales the first year when you advertise pre-launch people can get the improved model for cheaper at least six months after the launch, even if it ends up taking longer than six months. That's a self-inflicted wound.