I do wonder if Sonys ML upscaling solution is based on rumoured AMD solution that's releasing end of this year.
Maybe they worked on it together (maybe even with feedback from Sony studios) and Sony have tweaked it slightly to be a little more performant in a closed box, or it's something completely different.
But it would make sense for it to be shared technology and has many benefits for developing collaboratively such as shared development costs.
I speculated the same thing a few pages back. What I didn't realise at the time though is that Sonys ML capabilities in the Pro are according to the rumour "completely custom". Which would seem strange and rather pointless if RDNA 4 will be running the same or a very similar upscaling model.
There is the possibility though that the new ML functionality of RDNA4 simple wasn't ready in time for the Pro and so Sony had to go with a custom design - similar to the whole primitive shader vs mesh shader thing with PS5 and RDNA2.