I don't know what you mean by AV receiver + AMP + DAC.
If you mean AV receiver for say speaker, but then a AMP/DAC for headphones then there is a method I use (without e-ARC which hopefully one day will solve this all when on all bits in the chain).
Right now this build I am typing on uses a G-Sync PG348Q, but for Audio a Sony AV receiver via HDMI off the GPU for 5.1 Audio. The G-Sync monitor is connected via Displayport and 100hz / G-Sync work fine. The AV receiver is connected via HDMI on the same GPU and in the options menu I select the AV receiver and get the options to select 5.1 etc in the sound panel. The AV receiver is represented as a Phantom monitor within windows and Nvidia control panel. Hopefully below shows what I mean:
For DAC and AMP part, I also have optical going into the DAC from the motherboard which in turn goes into various AMPs which has no issues.
With that said, in the Living room I have a specific gaming HPTC, QLED TV along with a Dolby Atmos 5.2.2 setup. There things do not work quiet as smoothly. I can do the same connection type as above, i.e one HDMI into TV and another HDMI in to AV receiver but now and then get flickering after a while. Not sure if its down to using two HDMI's off the GPU rather then 1 DP / 1 HDMI /TV being HDR / 12 bit 4:2:2 etc, so with this method reverted to using GPU --> AV receiver into TV which works flawlessly with HDR and ATMOS, but no G-Sync / FreeSync pass through. So while I have got the method working perfect in PC above for years now with multiple monitors over time, something seems amis with my living room setup.