Most of those aren't usability. That's functionality. Even if the PS5 UI were visually identical to the PS4, the backend for managing downloads/uploads is completely different. The system shutdown/rest mode issues are related to the firmware's interaction with the PS5 hardware itself and has nothing to do with the visual design of the UI. Closing and opening apps and figuring out which are open could be better represented visually, but the console itself is designed to allow for getting into switching between games much faster than the PS4 could ever manage.
Make something less convenient has nothing to do with usability? Okay.