Definitely not a generational leap, but 2TF is more power than an entire PS4, and that's the difference when the PS5 is in boost mode, so the real world difference is likely a full 3TF which is almost a PS4 Pro, let's not also forget the 448GB/s memory bandwidth vs 560GB/s for XSX, that will have an impact on higher resolutions.
This is not how you should compare it.
Let's say you developed a game with assets (models, shaders, CPUs, physics, etc.) then you adjust those to run on target hardware at a specific resolution/frame rate.
So I'll say this: if you have a 1080p TV there should be no difference between those consoles - unless something stresses out the CPU too much, I assume that the PS5 will have some disadvantage there.
If you have a 4K TV dropping the resolution a bit lower (the difference is below 30%, some at worse it would be ) when the action get heated will probably make both versions of a game as stable as the other.
One thing that may also happen is the lowering of the fidelity of some effects here and there (still to a pretty high level).
One other thing that could happen with the much faster SSD is that some games that stream a lot of data may have to be pared down to work properly on the series x (again, probably some minor pop-ups or textures loading in the distance).
So I think that in the end there will be very little discernable difference between the two, not my favorite situation, but what else can we do?
I have a 4K HDR TV, while I see a difference when content is not at native resolution, this is nowhere the mess that it was when playing sub native resolution on a 1080p TV - so while I am not as thrilled about the potential of the PS5 as I was hoping, I am still convinced it will put up a good fight and that in the end they are "close enough".