It is really difficult to compare raw numbers like teraflops across generations, because we think about them differently,” says [Jason Ronald, Microsoft’s director of Xbox program management]. “In general on the GPU side the Xbox Series S is effectively the same performance as an Xbox One X GPU, but it brings all the next-gen features like ray tracing, VRS, mesh shaders, and obviously when you look at the massive leaps in CPU performance and I/O performance, that’s why Xbox Series S is designed to deliver that true next-gen experience just targeting a lower resolution than Xbox Series X.
The difference in this generation is that if Microsoft’s promises for the Xbox Series S and X hold true, we could be looking at a console period that truly favors framerates and visual quality over pure resolution. The Xbox Series S might be the greatest representation of exactly that, allowing players to get the higher framerates many want to see from the next generation of games.
Need not be that, its technically possible that game can generate dynamic metadata, and render in HDR and if connected to a 4K TV, it can pass on the data to the TV, and not perform a tone mapping from HDR to SDR. These are all technical, not sure what XBox will plan to support.