this is my scenario:

PC with nvidia 3080
AVR Denon X1500H
TV 4k120hz

My AVR doesn't support 4k120hz, so I connected the PC to the TV.
TV and the AVR have both HDMI ARC, if I use internal TV Netflix app, i got audio 5.1 via ARC.

How can I use a dolby audio from the PC to the AVR?
Now i use an spidf, but i've only compressed audio 5.1.
ARC doesn't work (PC see only audio 2.0 on TV)
The only way that I found is to connect PC to the AVR via HDMI on the onboard HDMI, and PC-TV via Nvidia, but i've to set duplicate monitor...is there any way to force only audio via hdmi without an external HW Audio Extractor?