FSR 4/DLSS/Xess is something else than a simple spatial image based scaler though.

If you haven't tried machine learning based upscalers do give it a try! The newest generation (DLSS 4.5/FSR 4.1) are in general preferred by users over a native image since they provide a far superior way of native AA.

AI based frame-gen is also very good. 4k/120 Hz (1080p/60 FPS rendered) is very doable on mid-range cards these days.