You missed a lot.
The PS5 is underperforming in Japan. While it isn't really getting enough stock it's software sales have been relative to the hardware installbase historically bad. Worse than any other console's software sales before.
The Switch basically completely dominates the Japanese software market.
I suggest taking a look at the most recent Famitsu thread here or at the Media Create threads on the Installbase forum.
https://www.installbaseforum.com/forums/threads/media-create-sales-week-51-2022-dec-19-dec-25.1281/
There you can get more info from people that are very well educated regarding the Japanese video game market specifically.
Regarding Playstation as a whole in Japan, it has been in decline since the PS3 and has reached an absolute lowpoint in 2021 in terms of hardware and software sales.
