VLC may passthrough but it still depends on your device audio settings. For example, if you’re using a firestick then VLC is your software decoding and the firestick settings are your hardware. Both need to be configured appropriately.
I started with a firestick and quickly realized my mistake. I have a 7.2 system with ceiling speakers and all. I had to upgrade to the Shield Pro so I could passthrough TrueHD audio. Now my AVR has the blue light illuminate on the front to let me know when I’m streaming uncompressed audio.