So basically what your saying is, GPU theoretical power alone as expected doesn't tell the whole story about performance. Should be obvious to anyone really
It's not that PS5 gpu is stronger than the 6600xt, but the rest of the system is allowing the PS5 gpu to use much more of it's peak theoretical power due to having more ram(12 vs 8) and more bandwidth. 6600xt has close bandwidth as PS5 but only using embedded ram, PS5 has that level of bandwidth just by default
GPU memory bandwidth should absolutely be considered part of the GPU's "theoretical power". And that bandwidth should be considered in the context of the GPU's resolution target. That's doubly important for RDNA2 with its infinity cache where its not only the speed (bandwidth) that is scaled for a specific resolution, but also the capacity. The 6600xt has been specifically scaled by AMD to hit its full potential at 1080p and hence it could be argued that its in that resolution where it should be compared to PS5 with higher resolutions adding a handicap that the GPU simply wasn't designed to cope with.