The PS5 version was better to begin with. It was still running at a higher resolution and better frame rate before the patch. It just had a shit imaging processing technique being used that they fixed.
1- That is subjective. PS5 at launch had a very very poor IQ, PS5 was working with a much less fps-demanding reconstruction method and with an IQ result far below XSX version. XSX (according to NXG itself) was also using higher resolution effects and hence the performance difference.
2- The PS5 IQ issues have not been resolved, they have only been "alleviated". The IQ still leaves a lot to be desired. They have simply increased sharpennig. IQ is still much worse than XSX pre patch.
3- With the patch, XSX has started to use the PS5 reconstruction method and with this it has gained in performance..... but it cannot be said that it has objectively improved the experience. The IQ cut has not been worth it, especially since the RT performance mode offered a very good experience and maintained a higher IQ than what XSX and PS5 now have in resolution mode. That is the reason that there are people who complain and why many XSX users are under the impression that the patch has caused a downgrade.
4-In quality mode the resolution was/is the same. Is slightly lower in performance mode but it could be the same because the XSX version keeps 60fps locked now. They have not even worried about optimizing and they simply limited themselves to changing the reconstruction method without touching resolution.
5- What they have done with the XSX version is the simple solution and minimal effort. And of course they have chosen a solution that has not been to the liking of the majority.