A few useful links for mixing audio and sending to Teams from a Mac.

How to share System Audio in Microsoft Teams | Bastian Kroggel

This is not about the pros and cons of Teams. This is not about whether it is better than Slack, Zoom, Google Meet, Rocket.Chat or Jitsi. It is about a single feature that is so widely used in Zoom that I did not even think a serious competitor can lack the function – sharing your system audio with your colleagues and audience while presenting something on your screen.

The use case for that is pretty easily outlined: Prerecorded videos, reruns of an earlier session, or just some basic background music – all of that exceeds the basic capabilities of Microsoft Teams in its current iteration.

Rogue Amoeba | Using Loopback to add audio to voice chat (VoIP)

Loopback enables you to combine the audio from multiple sources, including microphones and applications, then provide that combined audio to voice chat applications to be heard by all participants.

And

You won’t use the Pass-Thru source which is included by default, so remove it by clicking to highlight it, then pressing the Delete button.

I wonder if removing Pass-Thru makes much difference.

How to Send Computer Audio Over Skype or Zoom | Music Learning Hub

Audio Recording Setup | Preston Lamb Consulting, LLC

GitHub – ExistentialAudio/BlackHole: BlackHole is a modern macOS virtual audio driver that allows applications to pass audio to other applications with zero additional latency.

BlackHole is a modern macOS virtual audio driver that allows applications to pass audio to other applications with zero additional latency.