This matches with the rumors that PS5 was originally designed as a 2019 console, but had to be delayed into 2020, full RDNA 2 wouldn't have been ready if PS5 was designed as a 2019 console originally. Also explains why PS5 has a 350 watt power supply compared to 320 watt for Xbox Series X, even though Xbox Series X is more powerful and has locked clocks compared to variable clocks on PS5; if PS5 is only RDNA 1.5 (RDNA 1 with some RDNA 2 features), we know that RDNA 2 is more power efficient, which would explain why Xbox Series can get away with a smaller power supply in spite of the console being more powerful.
Can't give any credit at all to the 2019 rumour. The small difference in performance is entirely down to the number of CU's. Both are RDNA 2, the difference is PS5 implements custom versions of some of these technologies, so while MS can say that they have the only console supporting all the feature set that was on stage... well it's meaningless and obvious.
Obviously PS5 cannot support DirectX Ray Tracing, it doesn't use DirectX... a microsoft technology. Obviously it doesn't use Microsoft's Direct Storage either. So that's 2 parts of the RDNA 2 feature set PS5 is missing... but they have their own versions that may be equal or even surpass Microsoft's so... this isn't a win. This is a "we have different stuff" that's it. Different, not necessarily better or worse.
PS5 supports Ray Tracing (Custom version of DirectX Ray Tracing), PS5 has a blazingly fast SSD (Custom version of Direct Storage), PS5 also has it's own versions of Variable Rate Shading and Mesh Shading. It isn't missing features, it's using it's own versions.
As for 320w vs 350w I believe running more CU's at a lower clock speed like Xbox will be more power efficient than the PS5 running less CU's at higher clocks. There's also other areas where PS5 may require more power. It's SSD may use more, tempest audio engine, Wifi 6 over Wifi 5, and it even has an extra usb port (usb-c at that) over the Xbox Series X meaning a higher potential Watt Usage. (The extra USB-C port on it's own could account for 9 watts +).
320w vs 350w isn't indication that PS5 isn't using RDNA 2.
So in conclusion this is just a little bit of PR fluff that is being blown out of proportion. Microsoft uses the same implementations as they do on their PC so they support the same RDNA 2 feature set shown on stage at the event. PlayStation uses different implementations on their console.
This is not a better or worse, it's just a difference.