Bringing audio from obs to jitsi?

Systems:
Debian Bullseye on Librem !#v4
and MacOSX Big Sur on macbookPro 2020

the problem i am having is that when using an external cam (mevo) connected to my machines and external microphone - the video and audio are not synched

So i thought i could use obs to bring both sources in - sync them in obs and output to jitsi.
I am failing bringing the audio to jitsi.

some more details:

using OBS 26.1.2 on both

In both systems obs has a scene wtih two sources

  1. webcam connected via NDi
  2. External mic connected to the machine via a USB - this is picked up by obs and represented as a source, and it works in obs

obs has virtualcam option
using the obs virtual cam
i can bring obs video to jitsi
but failing to bring obs audio to jitsi

Any advice suggestion or resource to read is gratefully received

I want to use Jitsi with OBS OBS outputs video/ audio, but only to an SRT/RTMP/FTL server, or to a recording file.