An NVIDIA engineer has sent in pull requests to DXVK, VKD3D-Proton and DXVK-NVAPI to enable support for Reflex / NV low latency to get it hooked up in Proton.
For DXVK-NVAPI the pull request notes:
For VKD3D-Proton the pull request notes:
And then again the pull request for DXVK notes:
Nice to see NVIDIA jumping in directly to get this support worked on, and also good that they're not trying to overwrite support for the already existing LatencyFleX, which is an open source alternative to NVIDIA Reflex.