Cool GTX
Which browser?
Test ---> turn Off Hardware acceleration for Browser
I've done that in the past to fix Nvidia driver issues. This time, it seems like both Soundkeeper and NVCleaninstall, with Nvidia HD Audio device sleep timer disabled as well and enabling the Message Signaled Interrupts, seems to fix Dolby Atmos going robotic or completely dropping out. I've gotten two, second long audio drop outs so far - but that was just when alt tabbing or swapping browser tabs. If that's the worst, then it's acceptable compared to needing to disable the receiver in windows sounds or power cycling the receiver to get Dolby Atmos working again.
If the audio goes robotic, or completely drops out - I'll try with hardware acceleration disabled in Brave. Until then, I'm happy with the results so far, and I appreciate your help.