Edit: It fixed itself without me doing anything
Enabling DLSS in HDR mode* makes everything bright gray. Totally unplayable.
On the other hand DLSS in SDR works OK. Also HDR without DLSS looks nice.
*By HDR I mean D2R native HDR - not some external HDR remappers
RTX3080, 3900X, Win11, 32G RAM, UHD HDR @ 240Hz (everything updated)