Looks like it should do the trick, thanks!
Looking at that answerhub and the current code, it almost seems as if the implementation has changed since that answer was posted, because internally the voice system seems to be using an AudioComponent with an internal SoundWaveProcedural.
It appears that the thing that needs to be done is to set AllowSpatialization = true (instead of false) in CreateVoiceAudioComponent() in OnlineSubsystemUtils.cpp, as well as making sure that the transform is correctly updating.
I mention the above for others that are investigating this and might a bit confused about the answerhub link, because SoundWaveStreaming is now SoundWaveProcedural, and the internal VOIP implementation seems to be pretty close already to what they were talking about in the answerhub.