I play on an S my other half plays on an X and we’re side by side in the same room on the same server so we’ve kind of experimented a bit in comparing our game. Performance wise there doesn’t seem to be a noticeable difference, sometimes things seem to load quicker on the X (like accessing storage) but the graphics on the X are certainly better with a few extra graphics features (I’m jealous that I don’t get a moon at night! ) and the render distance seems to be better on the X - if we walk away from each other I can been seen on his screen but I can’t see him on mine for example. In contrast my visibility during in-game bad weather seems to be better, on the X we often have an almost completely black screen whereas I can still see a little in the fog/rain/nighttime
Not cold hard facts and more hearsay I’m afraid but that’s my experience of the difference between the two.