Thanks for this tip. This is a great thread for learning! I've been using Cinema mode for both SDR and HDR, but I just tried Bright Cinema for HDR content and it looks a bit more natural, but of course much too bright for SDR.
I also have an Epson with the HDR1-4 settings. Let me make a small correction. “Auto” mode automatically switches between SDR and HDR2. ”Auto (Bright)” mode switches between SDR and HDR1 which is what I use because HDR2 is too dark for my 9-foot wide screen-size.