Just thought I'd run the numbers quickly...
Just to be clear about why PS4 was 1080P and Xbox One was 900P in most games. PS4 has ~40% more flops, therefore capable of the 44% more pixels than Xbone.
Also, that's why XboneX games were often 4K when PS4 Pro games were 1800P. XboneX has ~45% more flops, therefore capable of the 44% more pixels than Pro.
I really don't know what XSX is going to do with just 17% more flops.
I think both will push 4K resolution as a minimum to be honest and maybe XSX will go for what, 2500P and downsample? Lol