Q90T Atmos works via eArc, but not from my PC

[surew1n]

My current setup is: PC to Q90T eARC port to Sonos Arc, all via HDMI 2.0 cables under 6ft.

TV expert sound settings set to Pass Through and Dolby Atmos on. My PC has Dolby Access installed and configured for home theater.

1. The Netflix apps in Windows and within the Samsung TV itself detect and play Atmos content.
2. But when I try to play Atmos content (ex. Dolby Leaf or Amaze trailer) from my PC through VLC/MPC-HC, and I change my spatial sound format to "Dolby Atmos for home theatre" - I do not get any sound at all.
3. The only way to hear sound is to set my Windows sound format to Stereo.

My assumption is that my PC only sees my the Q90T TV as stereo, and doesn't recognize that I have an Atmos capable soundbar connected to the TV via eArc. The Netflix Windows app somehow able to pass through correctly. I suspect that if I run an HDMI to my TV for video, and another HDMI to the Sonos Arc I could get past this, but this defeats the whole purpose of eArc.

Anyone have thoughts or suggestions? 

[Jacky Choo]

i have the exact same problem that disturbed me for a week so far.

i bought 3 units of Samsung QN900A , 85inch 8K. This is supposed to be the Flag ship model!!.

previously i was using LG OLED G and C series all the way, and the sound issues never occur at all. I am a pretty heavy user, so my TV setup will have a 3080Ti /PS5/XBX/Switch/AppleTV. All of these are definitely connected for a 4k 120hz experience, with HDR. 

i switched to Samsung because the bezels are so thin and there is native 8k but at 60hz should i want to view 8k content. I got a Sony HT A9 and a HT7000 connected to the PC. Totally no sound whenever Dolby Atmos is enabled at PC. No issues with TV app running Disney or Netflix. Just PC to TV via HDMI and only can get STEREO. 

wish samsung can really fix this. As my TV is mounted 2.5M away, i need to get 85 inches above. Either i switch to a C2 83/ G2 83 or wait for G2 98.