Oh yes, I've been over everything in your list, and much more, for over a year - except the cache clearing, which I'll try today.

My video card is used as an output direct to my Onkyo TX-RZ810 running the latest firmware. DP to HDMI adapter - a nice 8K one that replaced a passive 1080P one. The one HDMI port is direct to the TV. I've tried using the only HDMI port direct to the AVR, but I lose Gsync with the adapter (it doesn't function properly and the screen randomly blanks - I did contact their support to no avail).

I've got a new AVR on order that should be in next week, just to rule it out - a Denon X2800H. I'll even try using EARC on the TV, instead of a direct connection from the GPU. ARC didn't work going from.the GPU to the TV to the Onkyo, and I figured it was an ARC limitation.

Soundkeeper was going to be my next suggestion
 
Your MB have dedicated audio?  maybe skip the Nvidia sound for a test
 
Sure hope the new AVR finally resolves the issues

Cool GTX
Does it only happen after the PC has gone to sleep?  If you do a true cold boot does the issue Not happen, unless PC goes into: sleep or hibernate, first? Here you go  use NVCleanstall to reinstall your Nvidia driver  (I've been using this software for a long time, love the ability to limit the Nvidia bloatware & telemetry) Under "Installation Tweaks" select the "Disable Nvidia HD Audio device sleep timer"TECHPOWERUP --->NVCleanstall
Our free software lets you customize the NVIDIA GeForce Driver package by removing components that you don't need (or want). This not only keeps things tidy, but also lowers disk usage and memory footprint.
 
Disable Nvidia HD Audio device sleep timer

I haven't used PC sleep or hibernate in... 10 years? I turn that stuff off.
 
What I mean is that I can be watching a video or youtube stream, and while that sound is playing - it will drop out or go robotic. It happens when just watching. It does happen more often when alt tabbing or swapping browser tabs, but even when not doing that it can drop out or go robotic.
 
So far today, using Soundkeeper with the All argument seems to be working... so far. Supposedly it injects a constant stream of zeros that keeps any audio sources from sleeping (but I'm no software engineer - that's just how I interpret it).
 
That Enable Message Signaled Interrupts may or may not be the same thing. I really don't know, but I'll give it a shot while not running Soundkeeper (assuming NVCleaninstall doesn't mess things up (or I manage to mess up the install somehow)).

Why not use sleep or hibernate?  They are gifts from God.

ty_ger07
Why not use sleep or hibernate?  They are gifts from God.

Known bug for 3 years with sound & Nvidia drivers .... many experience the bug only after sleep or hibernate

Which browser?
 
Test ---> turn Off Hardware acceleration for Browser

arestavo

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.

Thanks for the update, I'm sure it can help others
 
I would like to suggest that you edit your first Post & include some = Tag your post: (bottom of screen)
 
That will help others find the solution, if / when they have a similar issue