^ I'm not going to quote your long post. All I can say is I have over 100 UHDs, most of them look great on my OLED and I can honestly say they all add something positive vs. the blu-ray. I was buying UHDs prior to having my OLED, knowing I'd upgrade eventually and I could still take advantage of any immersive mixes thanks to my Oppo 203. As much as I loved my Panny VT60, HDR was the game changer IMO more so than 4k. From what you describe you have an issue with your settings or a bad panel. Remember that this display won best HDR presentation at last year's shootout. Dynamic tone mapping has been improved for the C8, but the difference isn't that dramatic, it works pretty darn well on the B/C7. The Panasonic may help (remember the recommended setting for HDR is to use Dynamic Tone mapping on the LG and then set accordingly on the Panny), but from what you describe your issues lie elsewhere. There is a lot more at play than setting your light level. I have never felt the need to buy a Panasonic or viewed it as something that would make that big of difference unless I was a projector owner or owned a display that did 4k but not HDR.
First thought, I hope you turned off the energy saving mode (which is on by default) and it would be helpful to know what else you are doing - ie Cinema Home/Custom or Technicolor, etc. Have you tried the recommended settings found on this thread?
There is no perfect display, quit looking for faults and enjoy
LG OLED 65” B7 and 55” C8
Ascend's with RAAL, Love my PSA v1800 and a 7.2.4 speaker config, Oppo 203 and other stuff