As much praise the game gets on PC, it sounds like a From Software situation with tech that is not really a masterpiece, not nearly as good as the rest of the game. It looks fine I suppose but not mind blowing, this-is-pro-refresh-time good. Blaming mostly Larian for the coop debacle on XSS seems to be the right call. No MS engineer can fix stuff that is fundamentally not really anymore in the reach of the consoles the game was supposed to run on, when PS5, and presumably XSX, suffer too often too. Larian did a Crysis, aimed too high and did a terible optimisation for lower end, ie consoles. Crysis/cry-engine needed some heavy lifting to come on consoles in its next iteration and basically changed designed of the game world entirely. Larian should possibly not have included consoles at all if they were so limited in their manpower and expertise, almost like CD Project should not have included last gen. Which is imho just an utter failure in planning out your engine and optimisation requirements. Unless this can be fixed in a couple of weeks with some patches, but the concluded compromised XSS situation makes that unlikely in my view.
The engine seems to not have been made with consoles in mind.