Hello!
TAA and TSR implementation remains completly independent to ensure no TSR dev does not regress TAA on last gen consoles in terms of performance or quality.
Anytime I see aliasing only on some object in the scene, this is very often motion vectors like on your 5.1/5.2 comparion image. While 5.1 didn’t have the VisualizeTemporalUpscaler show flags that shows this sort of problem, it did have the VisualizeMotionBlur show flag that should help you quickly verify if this is the issue you are running into.