ULmark and their DLSS demos are load of rubbish. The TAA I've seen them implement is one of the worst ever and who the hell uses TAA in first place when there is MSAA, SMAA, TSSAA8TX, etc.
Compare 1440p vs 1440pDLSS and 4k vs 4kDLSS, not these fake4k upscaling where it's comparing 4k vs 1440pDLSS, of course 1440pDLSS is faster than rendering native 4k, duh!
Nvidia probably still waits to enable the DLSS2x which is the native DLSS mode without upscaling. They likely know every well it's slower or not really beneficial over traditional AA methods.