alt Hacker NewsI am not a graphics engineer so I hope someone corrects me, but my understanding is that Unreal uses a deferred rendering pipeline to handle complex lighting, and deferred renderers only work with temporal anti-aliasing.
The FSR/DLSS upscalers are typically superior to TSAA and are a reasonable replacement.
Deferred rendering requires a post process type antialiasing, can be TAA but also FXAA etc. It doesn't work with traditional MSAA.
A lot of the UE tech is built around the assumption of TAA though.