This sounds like the PS3 all over again.
Custom Hardware
Unique way of coding
Including previous console hardware for BC
More than 1 display at once
High price at launch
The price needs to be $400 just like with the PS4 and everything will be all right :)
It makes no sense to launch the PS5 PRO at launch of the normal PS5 since the tech will continue to move forward; so it will be better to make the PRO version 2-3 years later so that it has a significant enhancement.