Not able to watch this live--did they explicitly say PS5 is RDNA2?
Genuinely asking, sorry if I sound like I'm doubting.
Having throughout the previous presentations talked about next-gen consoles in terms of PS5 and Xbox Series X, David Wang then talked about RDNA2 as the common architecture of the next-gen consoles to enable easy portability of RT techniques between PC and consoles. He didn't specifically name-check any console in that part of the talk, but with all else we know about PS5's feature set, it's as close as confirmation as he could probably offer without Sony saying something themselves.
So, I wouldn't say explicit confirmation - but it tip-toed right up to that line, I think.