Graphically speaking, the Series X has only a very theoretical 15% power advantage; that's already half as small than X1/PS4 or X1X/PS4Pro, and without the RAM advantage PS4 and X1X enjoyed.
If this already tiny difference were to play out as is, this is how the two consoles would differ:
https://drive.google.com/drive/folders/1nZAF1kWhvAu3bZKbRZIKYIP0llf7nLIA
If you are selling "the world's most powerful console", that's fucking nothing.
You NEED impressive games to sell your image, because on paper performance is't going to do it.
Impressive games with graphical fidelity alone or with additional great features? Which I assume the PS5 will no doubt have that could put them in the better position to dominate again, but it's a wait and see situation that we should all take without declaring anything as fact.
This is pretty basic: if you want people to believe your system can do amazing things, you need to show amazing things.