You're exactly who I was hoping to hear from. I was beginning to wonder if I was the only one here who uses speakers and a display for PC gaming. The AVR-X8500H is virtually identical to the AVR-A110,
which I'm now using. I've watched vids on the G9, which is a flagship among mini LEDs. It's hard to imagine what playing BG3 on that would be like, especially when utilizing all that real estate. Perhaps you must turn your body, some rolling in your chair from end to end. Are you able to play in ultra mode (everything maxed) in that resolution with a 2080 Ti? If so, what FPS do you average?
If you do try out BG3 on your HT setup, please let me know what codec is displayed by your AVR, such as PCM, DD+, Dolby Atmos, stereo, etc. To use the native codec, you may need to set sound mode to AUTO using the Pure button on the remote. That's how I do it at least. But why would you choose a headset over using your 7.2.7 HT setup? Did you find a holy grail audiophile gaming headset? If so, please link. If it's about convenience, there are some handy options available for sofa gaming. Check out
this solution from couchmaster.