I don't think there's a possible NDA over a released product.
They wouldn't show up in Q3 2021 saying "you purchased this hardware 10 months ago, but we couldn't talk about it".
I don't rule out the idea of the PS5 having a nice custom feature. But they should be able to tell about how special it is.
My God ... this how works the NDAs is not guessing, many things could be hardware or software are never say it publically, of course
you cannot use that as an argument that X feature exists but even now exists a NDA for the API details of PS4.
We have years living with Sony and Nintendo, they are not like the companies in US which need to say each part of its features
the only need sometime the people who work in its products to know about its existence and how use it.
If not was for things like GDC we don't have idea about the details of the implementation of VRS in Call of Duty MW in current hardware.
Is not like you go with you doctor a demands he had to explain you or company who make some medicine how works in a protein level.