Seems this graphics glitch was due to DLSS dll version 310.4, used DLSS Swapper to switch to 310.21 (one version older) and that's perfect with Preset K and no glitches.
I'm now following the voice in the other world area, tose fast moving stabby things are gnarly.
Very much enjoying it, buttery smooth no traversal stutters, only the handful or initial shader comp hitches but nowhere near the 300ms shown on the DF video, more like 15ms ish? Small enough to ignore in the few times it happens.
Oh yeah did I mention OLED friendly black levels?