Hmm slight update on this as I got the game recently and now we have the update that added raytracing which is cool but to the bemusement of many who found it to tank the framerate considerably due to what appears to be poor optimisations. I found when HDR was enabled, everything else on max the game was pulling over 100fps easily at 3440x1440 - But if I then turned on raytracing, the fps dropped to 40 or even below that in busy areas.
If I turn off HDR but leave on RT, then the framerate goes back up to expected levels so it seems HDR mode is causing some issues with optimisation in this game when RT is also enabled.
Great game though, will play it with HDR off, also I find HDR isn't as nice as I expected it to be in this game, dark scenes are not pitch black, in fact non HDR mode looks darker than HDR mode, and that is even after adjusting the HDR brightness stuff.