I've been saying this since April when Sony first unveiled the PS5 that the GPUs in the both will likely end up around 12TFLOPS. For marketing reasons, it makes sense to at least say that the next boxes are 2x the graphical performance of the Xbox One X (even though we now all now that Navi is waaay more efficient so 12TFLOPS of Navi is likely ~16TFLOPS of Polaris). In terms of raw horsepower, we know that the next high end Navi cards from AMD is aiming to deliver 2080 Super level of performance as configured for PC. In typical console fashion, the cards will have to be paired down a bit for yields and power considerations so expect the consoles to be roughly based on the RX 5800 (or whatever it will be called) but with slightly less CU count and under-clocked when compared to the PC equivalent. With that said, we will still be looking at 2070 Super level perf at a minimum but more likely closer to RTX 2080 level (I would not be surprised if one console is slightly less powerful (i.e 2070 Super vs 2080 standard)). Yes, RTX 2080 level performance in a dedicated closed box console ?! Some amazing things to come!
U R NOT E
But here's the breakdown for those that may be confused: The RTX 2080 is ~10TFLOPs by Nvidia's calculations. However, we can extrapolate what an AMD Navi based card with similar power will measure in terms of TFLOPs. How? Just look at the specs vs perf between the RX 5700 XT and the RTX 2070 Super/ RTX 2080. The 5700 XT is ~9.7TFLOPs out of the box so let's say 10TFLOPs with an overlock (same at RTX 2080). Yet, according the the perf benchmarks at sites like
TechPowerUp, the RX 2070 Super is ~10% faster than the RX 5700XT (assuming a slight overclock to reach the 10 TFLOPs i.e. the Anniversary edition). Meanwhile the RTX 2080 is roughly 20% faster despite having the same TFLOPS measurement. So that means that AMD's Navi architecture is still roughly 20% less efficient than Nvidia's Turing. Thus, for AMD Navi to reach the 10TFLOPs perf of an RTX 2080, the Navi card will need to be roughly ~12TFLOPs (10TFLOPs + (10*0.2)).
Coincidence!?? I think NOT

As someone who has worked with PC hardware, software, and games professionally for over 10 years, I assure you it's not rocket science