EDIT2: Got a lot of people telling me it's loading time, idling, menus, etc. In some cases maybe, but there's no way that explains all those numbers. Also I never used my PS4 for anything besides gaming.
The other (more likely) explanation is that it counts time in rest mode, or maybe just part of it. Maybe the first two hours or something like that. Or whenever it's half booting to download an update or something. That could explain most of the numbers but is definitely an issue. The system should be able to recognize rest mode and stop the tracking accordingly. I'm curious to see how my tracking looks going forward to determine if the PS5 is better witn this than the PS4 was.