I haven't looked for workarounds, yet at least - but I think the desire is for the NDI stream to carry program audio over the network. For example, select a TC Mix output in Studio Monitor and you get the audio mix output - but select a Multiview and you don't.
I keep forgetting this and trying to share my UI via NDI over Teams, only to rediscover that no-one can hear my audio now, since it's routed through my TriCaster. And assigning my mic to a supplemental NDI output in TC's router won't help, either, since I can't choose that audio NDI stream separately in Virtual Input.