Pretty sure he said on a video the other day that it was actually the 7700XT that is closest, with the RDNA4 RT improvements, at roughly 40-50% faster than the 6700 which was close to the original PS5.
Edit:
Now bear in mind the 7700XT is currently a £300 GPU, so doesn't really make the case that the PS5 Pro is worth it, even in comparison to a PC, even including the RDNA4 RT improvements, which is maybe worth another say 20% value?
TPU puts the 7700XT at average 142% performance of the 6700, so that sounds about bang on TBH.
We will need to see pricing on RDNA4, but rumour has it AMD is trying to use the Blackwell delays and have it out in the next few months, at reasonable prices. If the RDNA4 7700XT equivalent comes out and costs £350-400, it's highlighting how much Sony is taking the **** as they'll be getting massive cost cuts on this stuff due to volume.