Since you mentioned voicemeeter, I did run into my own issues while using voicemeeter to control my audio devices. After this change, I was unable get any audio out of my Rift headphones from DCS. Normal audio from youtube or any other source functioned perfectly but DCS was just dead silent.
The fix I was able to find for it was to revert the drivers in voicemeeter to the MME drivers instead of the WDM drivers, which allowed DCS to divert to the rift headphones audio device, instead of my voicemeeter device and give me audio back.
So if anyone else is having similar issues with voicemeeter, try swapping from WDM to MME drivers...