The consensus here seems to always be leave in SDR and use match content, but I’ve had no issues with leaving Dolby Vision on all the time. SDR content like youtube and TV shows that were never mastered in HDR look 100% fine to me. Part of the Dolby Vision spec is that it forces your TV into it’s most color accurate settings so why wouldn’t I want that as well? Using an LG C2 by the way.
Cinema is the best but too dark for anything but pitch black room viewing in my experience. I prefer Cinema Home with the Dolby Precision Detail setting on which further boosts shadow detail and is intended for “bright room” viewing.
I use Cinema Home for the same reason. Unfortunately, my (old) CX doesn’t have Dolby Precision Detail. I believe LG introduced it with the C2. Fortunately, my apt faces east, so the room isn’t too bright except for a few morning hours. And I use Philips hue lights to control the lighting to enhance the viewing experience like a cinema scene that dims the lights to 15% and changes the color to red.