AFAIK, HDR was theorised by a third-party driver developer (iVRy) to have problems on AMD GPUs, so Sony disabled it. They also theorised that eye-tracking was disabled as SteamVR at the moment doesn’t support it (though it will be in the future), and that issues with USB communication was why they weren’t able to do it properly either with the adapter having a more direct connection. The adapter should be able to support it when SteamVR is updated, so hopefully Sony releases firmware updates for the adapter.

twitter.com/iVRy_VR (I’d provide a Nitter link but it’s playing up right now. Use whichever redirector extension if you’re that bothered.)