I can't recall any Ubisoft open world games running at 60fps on console. Series X is powerful but we can't expect some voodoo magic 8k 120fps box that also costs $400. It has 12 teraflops of power which is about the same as a GTX 1080 and that can only do 1440p/60fps on Oddesey. It also cost me $500 when it was new.
Here's how I think Series X will perform for most games.
Cost will be $450-500
You'll have the choice of:
-Dynamic 8k at an unstable 30fps
-4k at 60 fps (FPSs and less demanding titles)
-4k at 30fps (open world type games)
-1080p at up to 120fps option for some titles but who is going to use this one really.