That's some great work here, but I was referring to a different kind of aliasing,
mainly listed here. Wonder if spatial AA is applied in dissoccluded areas for UE5 (and in which branch). if you have a directional spatial upscaler in the TSR, such as FSR 1.0, prefiltering edges in previously occluded areas should help eliminate aliasing and improve quality in the regions where there is no temporal information. Another approach I prototyped for fun as a weekend project was repurposing
the MLAA algorithm for high quality spatial edge upscaling. Although there is some artifacting here and there (which I know is easy to fix but requires time), it works really well in combination with nearest neighbor upscaling for preserving contrast. Wish GPUs could export high res coverage sample mask at a few bits per pixel. Pixel perfect spatial upscaling would then be a trivial task == no low res aliasing on edges in motion.