Needless to say, this being a Microsoft owned studio, there was no favoritism given to the PS5 version in development.
Furthermore, since the PC version launched day and date with PS5, the developers already had their Direct X12 code ready to make improvements to the xbox Series X version over the PS5 for over a year now since DirectX12 is ubiquitous between PC and Xbox Series platforms according to MS.
The game was a financial disappointment with mixed to average reviews.
Why would they spend a ton of time on polish?
Far, but why would you even need to polish it? The game was finished!
The problem is everyone is quick to blames developers whenever a 3rd party game performs better on PS5 than Xbox Series X. Never mind the fact that those 3rd party developers manage to release those games on PS5/XSX at the same time.
In this case, the developers had a full extra year with Xbox Series consoles alone with the already finished game code. And we see this game performs significantly worse on Xbox Series X despite being from a first party Xbox developer having all the resources of MS/Xbox behind them.
So, it's not even about "polish", it's about people coming to grips with Xbox Series X actual capability vs their expectations when compared to PS5.